(a) Subject to subsection (b), the total number of enlisted members that may be assigned or otherwise detailed to duty as enlisted aides on the personal staffs of officers of the Army, Navy, Marine Corps, Air Force, and Coast Guard (when operating as a service of the Navy) during a fiscal year is the number equal to the sum of
(1) four times the number of officers serving on active duty at the end of the preceding fiscal year in the grade of general or admiral, and
(2) two times the number of officers serving on active duty at the end of the preceding fiscal year in the grade of lieutenant general or vice admiral.
