; and (2) if a determination under paragraph (1) is made that the total number of Federal employees exceeds such maximum, shall provide written notice of that determination to the President and Congress. (c) Compliance (1) In general Whenever, with respect to the quarter ending after September 30, 2018, the Office provides written notice under subsection (b)(2) that the total number of Federal employees exceeds the maximum number allowable under subsection (a), no agency may appoint any employee to fill any vacancy within such agency until the Office provides written notice to the President and Congress of a determination under subsection (b)(1) that the total number of Federal employees no longer exceeds the maximum number allowable under subsection (a). (2) Replacement rate To the extent necessary to achieve the workforce reduction required by this section, the Office, in consultation with the Office of Personnel Management, shall take appropriate measures to ensure that agencies shall appoint no more than 1 employee for every 3 employees retiring or otherwise separating from Government service after the date of the enactment of this Act. (d) Waiver for emergencies This section may be waived upon a determination by the President that— (1) the existence of a state of war or other national security concern so requires; or (2) the existence of an extraordinary emergency threatening life, health, public safety, property, or the environment so requires. (e) Definitions In this section— (1) the term agency means an Executive agency as defined by section 105 of title 5, United States Code, but does not include the Government Accountability Office; (2) the term Federal employee means an employee as defined by section 2105 of such title; (3) the term Office means the Office of Management and Budget; and (4) the term total number of Federal employees means the total number of Federal employees in all agencies.