| SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES | SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Medidata Solutions, Inc., together with its consolidated subsidiaries, (collectively, the “Company”) is the leading global provider of cloud-based solutions for clinical research in life sciences, offering platform technology that transforms clinical development and increases the value of its customers' research investments. The Company was organized as a New York corporation in June 1999 and reincorporated as a Delaware corporation in May 2000. Basis of Presentation — The accompanying consolidated financial statements include the accounts of the Company prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the rules and regulations of the Securities and Exchange Commission ("SEC"). All intercompany balances and transactions have been eliminated in consolidation. For purposes of these consolidated financial statements, the years ended December 31, 2018 , 2017 , and 2016 may be referred to as 2018 , 2017 , and 2016 , respectively. Use of Estimates — The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates. Revenue Recognition — Revenues are recognized when control of the promised goods or services are transferred to a customer, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods or services. The Company derives its revenues from two sources: (1) subscription revenues, comprised of subscription fees from customers utilizing the Company's cloud-based solutions; and (2) professional services, such as training, implementation, consulting, interface creation, trial configuration, data testing, reporting, procedure documentation, and other customer-specific services. The Company applies the following five steps in order to determine the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements: • identify the contract with a customer; • identify the performance obligations in the contract; • determine the transaction price; • allocate the transaction price to performance obligations in the contract; and • recognize revenue as the performance obligation is satisfied. Subscription The Company derives its subscription revenues from arrangements that grant the customer the right to utilize its cloud-based solutions for a specified term. Multi-study arrangements grant the customer the right to manage a predetermined number of clinical trials simultaneously for a term typically ranging from one to five years. Single-study arrangements allow customers to use the Company’s solutions on a per-trial basis. Subscription services are transferred to customers over time. The Company uses the passage of time as its measurement method because control of the services is transferred to the customer concurrently with the customer's use of the service throughout the contractual term. As a result, revenue for subscription services is recognized ratably over the term of the arrangement, which is generally aligned with the dates during which the customer has access to the Company’s cloud-based applications. Fees for subscription services are generally invoiced in advance installments with typical payment terms of net 30 or net 45 days . Professional Services The Company also makes available to its customers a range of professional services, including implementation, enablement, training, and strategic consulting. Professional services do not result in significant alterations to the underlying solutions. Professional services engagements involving implementation and training tend to be shorter term in nature (expected durations of less than one year), while enablement and consulting type engagements are longer in term (expected durations of one to five years). Professional services are transferred to customers over time. For fixed price arrangements, the Company measures its progress in transferring services to a customer using a proportional performance method. The proportional performance method is reflective of the variable rates at which services are transferred to the customer, and results in recognition of revenue that is consistent with the services provided to date. For time and materials contracts, the Company recognizes revenue as services are rendered. Fees for professional services are generally invoiced either in milestone installments based on work performed or, for time and materials based arrangements, as services are rendered, and typically have payment terms of net 30 or net 45 days. Performance Obligations The Company enters into contracts that contain multiple distinct performance obligations, combining a cloud-based technology subscription with various professional services. The Company has determined that its subscriptions and professional services are distinct performance obligations because both can be and are sold by the Company on a standalone basis, and because other vendors sell similar technologies and services on a standalone basis. For each performance obligation identified, the Company estimates the standalone selling price, which represents the price at which the Company would sell the good or service separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price by taking into account available information such as market conditions, review of historical pricing data, and internal pricing guidelines related to the performance obligations. The Company then allocates the transaction price among those obligations based on the estimation of standalone selling price. Transaction prices for the Company's contracts may include both fixed and variable consideration, but do not contain significant financing components or noncash consideration. Cost to Obtain and Fulfill a Contract The Company capitalizes expense associated with variable compensation paid to internal sales personnel that is incremental to obtaining and renewing customer contracts. Costs related to nonrenewable contracts are deferred and amortized on a straight-line basis over the duration of the contractual term. Costs related to initial signing and renewals of renewable contracts are deferred and amortized on a straight-line basis over a period equal to twice the term of the contract or renewal, which the Company deems to be the expected period of benefit for these costs. In developing this estimate, the Company considered its historical renewal rates and customer and revenue retention rates, as well as technology development life cycles and other industry factors. The current portion of capitalized contract costs is represented by prepaid commission expense on the Company's consolidated balance sheets; the long-term portion is included in other assets. These costs are periodically reviewed for impairment. Contract Balances Deferred revenue consists of billings or payments received in advance of revenue recognition and is recognized as the revenue recognition criteria are met. Amounts that have been invoiced are initially recorded in accounts receivable and deferred revenue. The Company invoices its customers in accordance with the terms of the underlying contract. Accordingly, the deferred revenue balance does not represent the total contract value of outstanding arrangements. Deferred revenue that is expected to be recognized during the subsequent 12-month period is recorded as current deferred revenue and the remaining portion as noncurrent deferred revenue. Stock-Based Compensation — The fair value of each nonvested restricted stock award ("RSA") or restricted stock unit ("RSU") is measured as if the RSA or RSU was vested and issued on the grant date. The related compensation expense is recognized, net of estimated forfeitures, on a straight-line basis over the vesting period. The fair value of each performance-based restricted stock unit ("PBRSU") with vesting that is dependent on the achievement of a market condition is estimated based upon the results of a Monte Carlo valuation model as of the grant date in accordance with accounting guidance. Compensation expense related to PBRSUs with a market condition is recognized, net of estimated forfeitures, on a straight-line basis over the vesting period. The fair value of each PBRSU with vesting that is dependent on the satisfaction of a performance condition is measured as if the PBRSU was vested and issued on the grant date, and is adjusted in each reporting period for expected performance relative to the associated goals. Compensation expense related to PBRSUs with a performance condition is recognized when it is probable that the condition will be achieved, net of estimated forfeitures, on a straight-line basis over the vesting period; the compensation expense ultimately recognized will equal the grant date fair value per share multiplied by the number of shares for which the performance condition has been satisfied. The fair value of each employee stock purchase plan ("ESPP") share is estimated using the Black-Scholes pricing model. The Company uses stock price volatility of its publicly-traded stock as a basis for determining expected volatility. Management believes this is the best estimate of the expected volatility over the weighted-average expected life of the ESPP shares. The expected life of each ESPP share is equivalent to the time between the beginning of the offering period and the end of the related purchase period. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the beginning of the offering period with a maturity tied to the expected life of the ESPP share. No dividends are expected to be declared by the Company at this time. Compensation expense for ESPP shares is recognized, net of estimated forfeitures, on a straight-line basis over their term. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes pricing model. The Company uses stock price volatility of its publicly-traded stock as a basis for determining the expected volatility. As of 2018, the Company's estimate of expected life for its stock options is based on an analysis of historical exercise data. In 2017 and prior, as the Company did not yet have sufficient historical exercise data with regard to its current option granting program, which is focused on new hires in key senior positions, to provide a reasonable basis upon which to estimate expected life, the Company used the simplified method permitted for plain-vanilla options under SEC Staff Accounting Bulletin ("SAB") 14. The risk-free interest rate is based on the United States ("U.S.") Treasury yield curve in effect at the time of the option grant with a maturity tied to the expected life of the options. No dividends are expected to be declared by the Company at this time. Compensation expense for stock options is recognized, net of estimated forfeitures, on a straight-line basis over the vesting period. Income Taxes — The Company's income tax expenses, deferred tax assets and liabilities, and liabilities for unrecognized tax benefits reflect management's best assessment of estimated current and future taxes to be paid. The objective for accounting for income taxes is to recognize the amount of taxes payable or refundable for the current year and deferred tax assets and liabilities for future tax consequences of events that have been recognized in the financial statements. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. Cash and Cash Equivalents — The Company considers all money market accounts and other highly liquid investments purchased with original maturities of three months or less to be cash and cash equivalents. The fair value of cash and cash equivalents approximates the amounts shown on the consolidated financial statements. Marketable Securities — The Company classifies its fixed income marketable securities as available-for-sale based on its intentions with regard to these instruments. Accordingly, marketable securities are reported at fair value, with all unrealized holding gains and losses reflected in stockholders' equity. If it is determined that an investment has an other-than-temporary decline in fair value, the Company recognizes the investment loss in other income (expense), net, in the consolidated statements of operations. The Company periodically evaluates its investments to determine if impairment charges are required. Accounts Receivable and Allowance for Doubtful Accounts — Accounts receivable are recorded at original invoice amount less an allowance that management believes will be adequate to absorb estimated losses on uncollectible accounts. The allowance is based on an evaluation of the collectability of accounts receivable and prior bad debt experience. Accounts receivable are written off when deemed uncollectible. Activity in the allowance for doubtful accounts for the three years ended December 31, 2018 was as follows (in thousands): 2018 2017 2016 Balance at beginning of period $ 1,454 $ 1,041 $ 1,992 Charged to costs and expenses 1,587 1,089 1,116 Deductions (1,042 ) (676 ) (2,067 ) Balance at end of period $ 1,999 $ 1,454 $ 1,041 Unbilled receivables consist of revenue recognized in excess of billings, substantially all of which is expected to be billed and collected within one year. As of December 31, 2018 and 2017 , unbilled accounts receivable of $38.6 million and $12.5 million , respectively, were included in accounts receivable on the Company's consolidated balance sheets. Entity-Wide Geographic Information — The Company operates as a single segment, as its chief operating decision maker reviews financial information that is presented on a consolidated basis. In accordance with required entity-wide disclosures, the following table summarizes long-term assets by geographic area as of December 31, 2018 and 2017 (in thousands): 2018 2017 Long-term assets: United States $ 428,862 $ 394,527 (1) United Kingdom 13,163 15,594 Japan 2,927 3,298 Korea 2,630 3,562 Germany 2,990 3,000 China 100 199 Singapore 55 36 Total $ 450,727 $ 420,216 (1) (1) Recast to reflect the Company's January 1, 2018 full retrospective adoption of ASC 606. The Company had no long-term assets in countries other than those listed above as of December 31, 2018 and 2017 . Refer to Note 3 , "Revenues" for December 31, 2018 , 2017 , and 2016 geographic revenue information. Restricted Cash — Restricted cash represents deposits made to fully collateralize certain standby letters of credit issued in connection with office lease arrangements. Software Development Costs — Costs incurred in the development and implementation of internal-use software are capitalized during the application development stage. Upgrades and enhancements to existing internal-use software are capitalized only if it is probable that those expenditures will result in additional functionality and future economic benefit. The Company capitalized $23.4 million and $19.0 million of internal-use software development and implementation costs in 2018 and 2017 , respectively. Capitalized software development costs are included in furniture, fixtures, and equipment on the Company's consolidated balance sheets; the resulting assets are initially included in construction in progress and are transferred to computer software upon release or go-live, at which time they are deemed to have been put into service and are depreciated on a straight-line basis over an estimated useful life of three to five years. Furniture, Fixtures and Equipment — Furniture, fixtures and equipment consist of furniture, computers, other office equipment, purchased and developed software for internal use, leasehold improvements, and construction in progress recorded at cost. Depreciation is computed using a straight-line method over five years for furniture and fixtures, and over three to five years for computer equipment and software. Leasehold improvements are amortized on a straight-line basis over the shorter of the lease term or their estimated useful lives. Improvements are capitalized while expenditures for repairs and maintenance are charged to expense as incurred. Construction in progress is not amortized into depreciation expense until it is placed into service. Goodwill and Intangible Assets — The Company has generated goodwill and certain intangible assets from various acquisitions. Goodwill represents the excess of consideration paid over the fair value of net assets acquired in business combinations. The Company evaluates its goodwill for impairment using a two-step process that is performed at least annually on October 1 of each year, or whenever events or circumstances indicate that impairment may have occurred. (The relevant accounting guidance also provides for an optional step zero that permits an entity to assess qualitative factors as a means of determining whether it is necessary to perform the two-step goodwill impairment test described below, but the Company does not currently utilize this option.) • The first step is a comparison of the fair value of the Company's single reporting unit with its carrying amount, including goodwill. If the fair value the reporting unit exceeds its carrying value, goodwill is not considered to be impaired and the second step is unnecessary. • If the carrying value of the reporting unit exceeds its fair value, a second test is performed to measure the amount of impairment by comparing the carrying amount of the goodwill to a determination of the implied value of the goodwill. The implied value of goodwill is determined as of the test date by performing a purchase price allocation, as if the reporting unit had just been acquired, using currently estimated fair values of the individual assets and liabilities of the reporting unit, together with an estimate of the fair value of the reporting unit taken as a whole. The estimate of the fair value of the reporting unit is based upon information available regarding the Company's market capitalization, prices of similar groups of assets, or other valuation techniques including present value techniques based upon estimates of future cash flow. If the carrying amount of the goodwill is greater than its implied value, an impairment loss is recognized for the difference. The Company determined that there was no impairment of goodwill for the years ended December 31, 2018 , 2017 , and 2016 , and did not recognize any impairments of goodwill in prior years. Acquired intangible assets are recorded at cost, derived from allocation of the purchase price of the acquired business to the intangible assets obtained based on their fair value, less accumulated amortization. Amortization of acquired technology is computed using the straight-line method over its expected useful life, which ranges from four to five years. Amortization of customer relationships is computed using the straight-line method over their expected useful lives, approximately six years. Amortization of trade name is computed using the straight-line method over its expected useful life, which is approximately fifteen years. Amortization of non-competition agreements is computed using the straight-line method over their contractual terms, which range from three to six years. Impairment of Long-Lived Assets — The Company reviews its long-lived assets, including furniture, fixtures and equipment (inclusive of capitalized internally developed software) and intangible assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The Company subjects a long-lived asset to a test of recoverability based on undiscounted cash flows expected to be generated by such asset while utilized by the Company and cash flows expected from disposition of such asset. If the resulting fair value is less than the carrying value of the asset, the asset is written down to fair value and a loss is recognized for the amount of the difference. There was no material impairment of long-lived assets for the years ended December 31, 2018 , 2017 , and 2016 . Treasury Stock — Shares of the Company's common stock that are repurchased are recorded as treasury stock at cost and included as a component of stockholders' equity. Refer to Note 4 , "Stockholders' Equity," for further information. Foreign Currency Translation — The reporting currency for the Company is the U.S. dollar. The functional currencies of the Company's subsidiaries in the United Kingdom, Japan, Korea, Singapore, China, and Germany are the British pound sterling, Japanese yen, South Korean won, Singapore dollar, Chinese yuan, and Euro, respectively. Accordingly, the assets and liabilities of the Company's foreign subsidiaries are translated into U.S. dollars using the exchange rate in effect at each balance sheet date. Revenue and expense accounts of the Company's foreign subsidiaries are translated using an average rate of exchange during the period. Foreign currency translation adjustments are accumulated as a component of other comprehensive income (loss) as a separate component of stockholders' equity. Gains and losses arising from transactions denominated in foreign currencies are recorded directly to the statement of operations. Fair Value of Financial Instruments — The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, and accrued liabilities approximate fair value because of the short maturity of these instruments. Fair values of marketable securities are based on unadjusted quoted market prices or pricing models using current market data that are observable either directly or indirectly. All methods of assessing fair value result in a general approximation of value, and such value may never actually be realized. The Company uses a three-level framework for measuring the fair value of its financial assets and liabilities that gives highest priority to Level 1 and lowest priority to Level 3 inputs, described as follows: Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 - Other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, including: • quoted prices for similar assets or liabilities in active markets; • quoted prices for identical or similar assets or liabilities in markets that are not active; • inputs other than quoted prices that are observable for the asset or liability; and • inputs that are derived principally from or corroborated by observable market data by correlation or other means. If the asset or liability has a specified (contractual) term, the Level 2 inputs must be observable for substantially the full term of the asset or liability. Level 3 - Unobservable inputs to the valuation methodology that are significant to the fair value measurement for the asset or liability. Concentration of Credit Risk — Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, and accounts receivable. The Company has policies that limit the amount of credit exposure to any one issuer. The Company performs ongoing credit evaluations of its customers and maintains an allowance for potential losses, but does not require collateral or other security to support customers' receivables. The Company's credit risk is further mitigated because its customer base is diversified both geographically and by industry sector. In 2018 , 2017 , and 2016 , no single customer generated more than 10% of the Company's total revenues . At December 31, 2018 and 2017 , no single customer accounted for greater than 10% of accounts receivable. The majority of the Company's cash, cash equivalents, and restricted cash are deposited with major U.S. financial institutions and, at times, balances with any one financial institution may be in excess of Federal Deposit Insurance Corporation ("FDIC") insurance limits. In addition, as of December 31, 2018 and 2017 approximately $4.5 million and $3.7 million , respectively, in cash and cash equivalents was deposited with foreign financial institutions and therefore not protected by FDIC insurance. Indemnifications — The Company indemnifies its customers against claims that cloud-based solutions or services made available by the Company infringe upon a copyright, patent, or the proprietary rights of others. In the event of a claim, the Company agrees to obtain the rights for continued use of the solutions for the customer, to replace or modify the solutions or services to avoid such claim, or to provide a credit to the customer for the unused portion of the subscription. A liability may be recognized if information prior to the issuance of the consolidated financial statements indicates that it is probable that a liability has been incurred at the balance sheet date and the amount of the loss can be reasonably estimated. No such liabilities were recorded as of December 31, 2018 and 2017 . Recently Adopted Accounting Pronouncements — In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers , which supersedes the existing accounting standards for revenue recognition in Accounting Standards Codification ("ASC") 605, and provides principles for recognizing revenue for the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. ASU No. 2014-09 also creates a new subtopic under ASC 340, Other Assets and Deferred Costs , which discusses the deferral of incremental costs of obtaining a contract with a customer, including the period of amortization of such costs. The Company adopted ASU No. 2014-09 on January 1, 2018, using the full retrospective method. Refer to Note 3 , "Revenues," for related disclosures. The following tables summarize the impact of adoption of ASC 606 on the Company’s consolidated balance sheet as of December 31, 2017 (in thousands): As of December 31, 2017 As Reported Under ASC 605 Impact of ASC 606 Adoption As Adjusted Assets Current assets: Prepaid commission expense $ 5,352 $ 7,052 $ 12,404 Prepaid expenses and other current assets 37,287 (3,651 ) 33,636 Noncurrent assets Deferred income taxes – long-term 40,847 (5,058 ) 35,789 Other assets 29,979 16,776 46,755 Liabilities Current liabilities: Deferred revenue 77,434 (59 ) 77,375 Stockholders' equity: Retained earnings $ 146,739 $ 15,178 $ 161,917 The following tables summarize the impact of adoption of ASC 606 on the Company’s consolidated statements of operations for the years ended December 31, 2017 and 2016 (in thousands, except per share amounts): Year Ended December 31, 2017 Year Ended December 31, 2016 As Reported Under ASC 605 Impact of ASC 606 Adoption As Adjusted As Reported Under ASC 605 Impact of ASC 606 Adoption As Adjusted Revenues Subscription $ 459,528 $ (1,704 ) $ 457,824 $ 394,269 $ (5,272 ) $ 388,997 Professional services 86,004 377 86,381 69,112 384 69,496 Total revenues 545,532 (1,327 ) 544,205 463,381 (4,888 ) 458,493 Operating costs and expenses Sales and marketing 126,273 (2,135 ) 124,138 109,290 (3,365 ) 105,925 Operating income 64,348 808 65,156 50,209 (1,523 ) 48,686 Provision for income taxes 7,847 (2,388 ) 5,459 8,331 (549 ) 7,782 Net income $ 44,380 $ 3,196 $ 47,576 $ 28,983 $ (974 ) $ 28,009 Earnings per share Basic $ 0.79 $ 0.05 $ 0.84 $ 0.52 $ (0.02 ) $ 0.50 Diluted $ 0.74 $ 0.06 $ 0.80 $ 0.51 $ (0.02 ) $ 0.49 The adoption has no cash flow impact. In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which amends certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. ASU No. 2016-01 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. The Company adopted ASU No. 2016-01 on January 1, 2018, and the adoption did not have a material impact on its condensed consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Cash Flows - Classification of Certain Cash Receipts and Cash Payments , which addresses the diversity in practice around presentation of certain cash receipts and payments in the statement of cash flows. ASU No. 2016-15 is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. The Company adopted ASU No. 2016-15 on January 1, 2018, and the adoption did not have a material impact on its condensed consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business , which provides a more specific definition of a business than was afforded under previous guidance. The definition of a business affects many areas of accounting, including acquisitions, disposals, goodwill, and consolidation. ASU No. 2017-01 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The Company adopted ASU No. 2017-01 on January 1, 2018, and the adoption had no impact on its condensed consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting , which clarifies when a change in the terms or conditions of a share-based payment award should be accounted for as a modification. ASU No. 2017-09 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The Company adopted ASU No. 2017-09 on January 1, 2018, and the adoption did not have a material impact on its condensed consolidated financial statements. In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting, which simplifies several aspects of the accounting for nonemployee share-based payment transactions by expanding the scope of the stock-based compensation guidance in ASC 718 to include share-based payment transactions for acquiring goods and services from non-employees. ASU No. 2018-07 is effective for annual periods beginning after December 15, 2018, including interim periods within those annual periods. Early adoption is permitted, but entities may not adopt prior to adopting the new revenue recognition guidance in ASC 606. The Company early adopted ASU No. 2018-07 in the second quarter of 2018, and the adoption did not have a material impact on its consolidated financial statements. Recently Issued Accounting Pronouncements — In February 2016, the FASB issued ASU No. 2016-02, Leases , which replaces previous lease guidance in its entirety with ASC 842 and requires lessees to recognize lease assets and lease liabilities for those arrangements classified as operating leases under previous guidance, with the exception of leases with a term of twelve months or less. ASU No. 2016-02 is effective for annual periods beginning after December 15, 2018, including interim periods within those annual periods. Originally, entities were required to adopt ASU No. 2016-02 using a modified retrospective method; however, in July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements , which provides entities with an additional choice of transition method. Under ASU No. 2018-11, entities have the option of recognizing the cumulative effect of applying the new standard as an adjustment to beginn |
