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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other enforcement action and to enter into, or permit, the settlement of any such litigation or other enforcement action with respect to its Intellectual Property . D. Each Party shall promptly notify the other Party in writing if any claim, action, demand or other proceeding (a "Claim") is brought against or is threatened to be brought against such Party alleging that the sale of Product violates another party's intellectual property. E. SCIEN will promptly notify HEMISPHERX of any Third party SCIEN knows or believes may be infringing HEMISPHERX Intellectual Property and will, to the greatest extent reasonably possible, provide to HEMISPHERX any information SCIEN has in support of such belief. HEMISPHERX will have the right, but not the obligation, to use such information in an infringement action against such third Party. SCIEN agrees to cooperate with HEMISPHERX in any action for infringement of HEMISPHERX, and HEMISPHERX will reimburse SCIEN for all reasonable costs incurred by it in providing cooperation requested by HEMISPHERX. {***} Confidential portions of this exhibit have been redacted and filed separately with the Commission pursuant to a confidential treatment request in accordance with Rule 24b-2 of the Securities Exchange Act of 1934, as amended. Page 8 of 28 F. HEMISPHERX is and shall remain the sole legal and registered owner for any trademark or trade name of "Interferon alfa-n3 (human leukocyte derived)". The parties shall work together, upon commercial approval in the Territory to secure a trade name in the Territory. G. HEMISPHERX hereby grants to SCIEN and SCIEN hereby accepts the right, privilege and exclusive license to use of "Interferon alfa-n3 (human leukocyte derived)" solely in connection with the terms of the Sales, Marketing, Distribution and Supply Agreement of Product in the Territory for the Term of this Agreement. Should the Agreement expire or terminate, the right to use the trademark shall also terminate. SCIEN shall use "Interferon alfa-n3 (human leukocyte derived)" at all times for the sole purpose of marketing of Product for no other purpose. H. The terms of the intellectual property license hereby granted shall be effective upon the Effective Date of this Agreement and during the term of this Agreement, unless sooner terminated in accordance with the provisions of the Sales, Marketing, Distribution and Supply Agreement between the parties. 1. Good Will. SCIEN recognizes that there exists great value and good will associated with the Intellectual Property of Interferon alfa-n3 (human leukocyte derived)" 2. SCIEN agrees that it will not during the term of this Agreement, or thereafter, attack the title or any rights of HEMISPHERX in and to Interferon alfa-n3 (human leukocyte derived) or attack the validity of the license granted herein by HEMISPHERX and solely owned by HEMISPHERX. I. SCIEN agrees to assist HEMISPHERX to the extent necessary in the procurement of any protection or to protect any of HEMISPHERX's right to Interferon alfa-n3 (human leukocyte derived) and HEMISPHERX, if it so desires, may commence or prosecute any claims or suits in its own name or in the name of SCIEN or join SCIEN as a party thereto. SCIEN shall notify HEMISPHERX in writing of any infringements or imitations by others of "Interferon alfa-n3 (human leukocyte derived) which may come to SCIEN 's attention, and HEMISPHERX shall have the sole right to determine whether or not any action shall be taken on account of any such infringements or imitations. SCIEN shall not institute any suit or take any action on account of any such infringements or imitation without first obtaining the written consent of the HEMISPHERX so to do. J. SCIEN agrees to cooperate fully and in good faith with HEMISPHERX for the purpose of securing and preserving HEMISPHERX's rights. K. It is agreed that nothing contained in this Sales, Marketing, Distribution, and Supply Agreement shall be construed as an assignment or grant to the SCIEN of any rights, title or interest in or to "Interferon alfa-n3 (human leukocyte derived)". L. It is further understood that all rights relating thereto are reserved by HEMISPHERX, except for the license hereunder to SCIEN of the right to use and utilize the name Interferon alfa-n3 (human leukocyte derived) only as specifically and expressly provided in this Agreement. M. In the event of termination of this license for any reason, SCIEN shall within 6months (as described in the Termination clause), cease all use of the "Interferon alfa-n3 (human leukocyte derived)". SCIEN shall not thereafter use any names, mark or trade name similar thereto belonging to HEMISPHERX. Termination of the license under the provisions of
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Extract the exact clause related to "Covenant Not To Sue" from the excerpt above.