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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eligible for a [***]. 8.4 Milestone Payment for [***]. If CytoDyn receives [***], then Vyera shall pay to CytoDyn [***] (the "[***]") in immediately available funds upon the receipt of [***]. CytoDyn shall promptly notify Vyera in writing following receipt of [***] and submit to Vyera an invoice for the corresponding milestone payment set forth in this Section 8.4. Within thirty (30) days of Vyera's receipt of any such invoice, Vyera shall remit the milestone payment to CytoDyn. The [***] shall be non-refundable and non-creditable. 8.5 Milestone Payment for [***]. With respect to any [***] for the Licensed Product within the Field other than the [***], the JC shall determine in good faith (which determination, for the avoidance of doubt, shall not be a Reserved Dispute of either Party) the amount of the payment, if any, payable by Vyera to CytoDyn in the event [***] is received. Such payment as recommended by the JC shall be approved by the management of each Party. CytoDyn shall promptly notify Vyera in writing following receipt [***] for which payment has been agreed and approved and submit to Vyera an invoice for the corresponding milestone payment that the Parties have agreed upon pursuant to this Section 8.5. Within thirty (30) days of Vyera's receipt of any such invoice, Vyera shall remit the milestone payment to CytoDyn. Each milestone payment for a [***] shall be non-refundable and non-creditable. Notwithstanding the foregoing, in the event that the JC is unable to agree on whether to pursue a [***], the decision as to whether to pursue a [***] shall be made by CytoDyn in its sole discretion provided, however, that such [***] will not be eligible for a milestone payment pursuant to this Section 8.5. 8.6 Royalty Obligation. Vyera shall pay to CytoDyn royalties equal to fifty percent (50%) of Net Sales of Licensed Products in the Territory during the Royalty Term; provided that, after the Step-Down Date, the royalty percentage will be reduced to [***] of Net Sales of Licensed Products in the Territory throughout the remaining period in the Royalty Term. Royalties shall be payable commencing upon the First Commercial Sale of the Licensed Product in the Territory until the expiration of the Royalty Term in the Territory. Following the expiration of the Royalty Term with respect to the Licensed Product, the licenses granted under Section 2.1 with respect to such Licensed Product in the Field and the Territory shall be non-exclusive, perpetual, irrevocable, fully-paid and royalty-free. Source: CYTODYN INC., 10-Q, 1/9/2020 8.7 Required Licenses. If either Party receives a notice from a Third Party indicating that the Commercialization of a Licensed Product in the Field in the Territory infringes a Third Party Patent, it will promptly notify the other Party. The Parties will thereafter discuss a response in good faith. If the Parties agree in good faith that it is reasonable to enter into a license with such Third Party to avoid infringement of such Third Party patent(s)by the sale, offer for sale or use of a Licensed Product in the Field in the Territory (each such license, a "Required Third Party License"), then CytoDyn shall have the right to negotiate the terms of such Required Third Party License and the amounts payable under such Required Third Party License shall be deducted from the royalties payable to CytoDyn. If either of the Parties agree in good faith that it is not reasonable to enter into a license with a Third Party to avoid infringement by the sale, offer for sale or use of a Licensed Product in the Field in the Territory, any fees, costs or expenses incurred by either Party, including, without limitation, damages as a result of an infringement claim, will be borne by CytoDyn in accordance with Section 13.2. If the Parties agree in good faith that it is appropriate to bring an opposition, action for declaratory judgment, nullity action, interference, declaration for non-infringement, re- examination or other attack upon the validity, title or enforceability of a patent owned or controlled by a Third Party based on its' potential adverse impact on the patent freedom-to-operate with respect to the Commercialization of a Licensed Product in the Field in the Territory, then CytoDyn shall control such action and shall be responsible for the costs of such action. CytoDyn shall provide Vyera with copies of any substantive documents related to such proceedings and reasonable notice of all such proceedings. Vyera may itself or through its counsel offer comments and suggestions with respect to
"""

Extract the exact clause related to "Irrevocable Or Perpetual License" from the excerpt above.

assistant: Following the expiration of the Royalty Term with respect to the Licensed Product, the licenses granted under Section 2.1 with respect to such Licensed Product in the Field and the Territory shall be non-exclusive, perpetual, irrevocable, fully-paid and royalty-free.