; and (bb) debate on a veto message in the Senate under this paragraph shall be 1 hour equally divided between the majority and minority leaders or their designees. (D) Extension of 48-hour period for exigent circumstances If either chamber is adjourned when the 48-hour period begins and cannot practicably reconvene in time to consider approval legislation in accordance with this subsection during the 48-hour period, and if all of the congressional leaders, or their designees, reach an agreement under which they, or their designees, determine that the action under subsection (a), (b), (c), or (d) to which such notification relates is necessary to protect against an imminent and specific threat to human life or an imminent and specific threat to national security, and that the 48-hour period will be extended until such time as they, or their designees, consider practicable, such period shall be extended until such time. Such agreement shall be provided to the President, the Members of the House of Representatives and Senate, and each senior Government official. (E) Supermajority required In the Senate and the House of Representatives, the approval legislation may only be adopted (including in the case of adoption by one House of approval legislation received from the other House, with or without amendment) by an affirmative vote of not less than— (i) three-fifths of the Members of each respective chamber, duly chosen and sworn