system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
"""
EXHIBIT 10.3 Yield Maintenance Agreement [LOGO UBS] Date: 27 April 2006 To: Wells Fargo Bank, N.A., not individually, but solely as Master Servicer on behalf of Wells Fargo Mortgage Backed Securities 2006-6 Trust ("Counterparty") Attention: Swaps Administration From: UBS AG, London Branch ("UBS AG") Subject: Interest Rate Cap Transaction UBS AG Ref: 37346733 Dear Sirs The purpose of this communication is to confirm the terms and conditions of the Transaction entered into between us on the Trade Date specified below. This Confirmation constitutes a "Confirmation" as referred to in the Master Agreement or Agreement specified below. The definitions contained in the 2000 ISDA Definitions as published by the International Swaps and Derivatives Association, Inc., are incorporated into this Confirmation. In the event of any inconsistency between any of the definitions listed above and this Confirmation, this Confirmation will govern. If you and we are parties to a master agreement that governs transactions of this type (whether in the form of the 1992 ISDA Master Agreement (Multicurrency-Cross Border)(the "ISDA Form") or any other form (a "Master Agreement"), then this Confirmation will supplement, form a part of, and be subject to that Master Agreement. If you and we are not parties to such a Master Agreement, then you and we agree to use all reasonable efforts promptly to negotiate, execute and deliver an agreement in the form of the ISDA Form, with such modifications as you and we will in good faith agree. Upon the execution by you and us of such an agreement, this Confirmation will supplement, form a part of and be subject to and governed by that agreement, except as expressly modified below. Until we execute and deliver that agreement, this Confirmation, together with all other documents referring to the ISDA Form (each a "Confirmation") confirming transactions (each a "Transaction") entered into between us (notwithstanding anything to the contrary in a confirmation), shall supplement, form a part of, and be subject to an agreement in the form of the ISDA Form as if we had executed an agreement in such form (but without any Schedule except for the election of the laws of New York as the Governing Law and U.S. Dollars as the Termination Currency) on the Trade Date of the first Transaction between us (hereinafter the "Agreement"). In the event of any inconsistency between the provisions of any such Agreement and this Confirmation, this Confirmation will prevail for the purposes of this Transaction. The terms of the particular Swap Transaction to which this Confirmation relates are as follows: General Terms Trade Date: 27 April 2006 Effective Date 01 April 2006 Termination Date: 1 April 2009 Calculation Amount: The lesser of (a) USD 20,000,000.00 and (b) the aggregate Principal Balance (as defined in the Pooling and Servicing Agreement) of the Class I-A-22 Certificates as of the last day of the relevant Calculation Period. Seller of the Cap: UBS AG Buyer of the Cap: Counterparty Calculation Agent: UBS AG Business Days: New York Broker: None Fixed Amounts Fixed Rate Payer: Counterparty Fixed Amount: USD[ ] Fixed Rate Payer Payment Date: 27 April 2006 Business Day Convention: Not Applicable Floating Amounts Floating Rate Payer: UBS AG Cap Rate: 5.0 percent per annum Floating Amount: To be determined in accordance with the following formula: Greater of (1)Calculation Amount * Floating Rate Day Count Fraction * (Floating Rate Option - Cap Rate) and (2) 0 Floating Rate Option: USD-LIBOR-BBA Designated Maturity: One Month Spread: None Floating Rate Day Count 30/360 Fraction: Floating Rate Payer Period 01 January, 01 February, 01 March, 01 April, End Dates: 01 May, 01 June, 01 July, 01 August, 01 September, 01 October, 01 November and 01 December, in each year, from and including 01 May 2006, up to and including the Termination Date, subject to adjustment in accordance with the Business DayConvention specified immediately below, and thereshall be No Adjustment to the Period End Dates. Floating Rate Payer Payment Delayed Payment shall be applicable. The Dates: FloatingRate Payer Payment Dates shall be two Business Days prior to 25 January, 25 February, 25 March, 25 April, 25 May, 25 June, 25 July, 25 August, 25 September, 25 October, 25 November and 25 December, in each year, from and including 25 May 2006, up to and including 25 April 2009, notwithstanding the specified &bbsp; Termination Date, subject to adjustment in accordance with the Business Day Convention specified immediately below. Reset Dates: First day of each Calculation Period. Business Day Convention: Modified Following Additional Provisions (i) "Specified Transaction" shall have
"""

Extract the exact clause related to "Document Name" from the excerpt above.

assistant: Yield Maintenance Agreement