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:
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delay or additional costs that may be generated. 8 CLAUSE THIRTEENTH SUSPENSION DUE TO NON-PERFORMANCE OF THE SENDER 13.1 ECOPETROL shall be entitled to suspend the Service in case of any events that may represent a serious default on any of the obligations of the SENDER. For this purpose, a communication from ECOPETROL addressed to the SENDER shall be sufficient, notifying the serious default. ECOPETROL may, based on the seriousness and the effects of the default, grant the SENDER a reasonable term to fix the default (the "Grace Period"), which under no circumstance may be granted if the default is due to the non-payment of the Fee in the terms set out in the Contract hereof. If, upon expiration of the Grace Period the SENDER has not resolved the default, ECOPETROL may suspend the Service and the SENDER shall not be entitled to any indemnification under no circumstance. The reestablishment of the provision of Services shall be subject to previous approval in writing by ECOPETROL. 13.2 The suspension of the Contract is not a waiver or a release for the SENDER on its responsibility to pay the Fee and all other concepts that may be applicable under the Contract hereof. CLAUSE FOURTEENTH TERMINATION OF THE CONTRACT 14.1 The Contract hereof shall terminate upon expiration of the term of validity agreed. 14.2 The Parties agree that ECOPETROL may declare the termination in advance of the Contract at any time, without any indemnity in favor of the SENDER in the following events: a) Serious default of the obligations of the SENDER without solving them within the Grace Period, when it may apply. b) The dissolution of the SENDER as a legal person. c) The unauthorized assignment of the Contract by the SENDER. d) Due to changes in regulations making more costly the fulfillment of obligations undertaken by ECOPETROL. e) As a consequence of any of the following causes: (i) fraud of the SENDER; or (ii) the SENDER incurs in acts or conducts that may endanger the operational and/or technical stability of the Pipelines. f) The procedure to be followed by ECOPETROL to terminate the Contract is: notify in writing with at least thirty (30) calendar days in advance to the SENDER its intention to terminate the Contract, indicating the causes for such decision and the effective date of termination. Upon fulfillment of this procedure the SENDER shall not: (i) request any justifications or extensions to the motives explained by ECOPETROL, or (ii) request or demand any kind of compensation or damages derived from the decision to terminate the Contract. g) The termination shall not release the Parties from its corresponding obligations and responsibilities attributable to periods before the date of termination of the Contract. 9 14.3 It shall not be necessary any previous private or judicial requirement for purposes of enforcement of this clause. CLAUSE FIFTEENTH TAXES 15.1 All taxes, contributions, rates, surcharges and any other national, departmental, district or municipal taxes caused by the entering into, execution and liquidation of the Contract hereof, shall be borne by the Party that has to assume said payment pursuant to the law. 15.2 The collection and payment of the shipment tax shall be assumed by ECOPETROL before the Ministry of Mines and Energy, and therefore the SENDER shall pay the same to ECOPETROL pursuant to the provisions hereto. CLAUSE SIXTEENTH LIQUIDATION OF THE CONTRACT 16.1 Upon expiration of the Term of Validity, the Parties shall subscribe the minutes of termination of the execution. 16.2 The Parties shall make the liquidation of the Contract by mutual agreement within three (3) months following the expiration of the date of termination of the Contract. 16.3 In case the SENDER fails to appear to the liquidation, or if there is not an agreement of the same within the term previously mentioned, the SENDER expressly authorizes ECOPETROL to proceed with the liquidation in one (1) month term. 16.4 The following shall be expressly stated in the minutes of liquidation: 16.5 Upon liquidation of the Contract, the SENDER shall pay ECOPETROL any Fees or any amount of money owed or resulting from the final liquidation of the same, after making any deduction that may be applicable. h) The termination in advance of this Contract shall not release the SENDER from the obligations that survive the termination of the Contract, especially that related with the payment of the Fee pending of payment and the payment of the penal clause. In the event of termination in advance of the Contract, the SENDER
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Extract the exact clause related to "Irrevocable Or Perpetual License" from the excerpt above.