; (2) the term initial contract year has the meaning given the term in section 8903c(a) of title 5, United States Code, as added by section 101 of this Act; (3) the term Medicare cost-sharing means Medicare cost-sharing described in section 1905(p)(3)(A)(ii) of the Social Security Act ( 42 U.S.C. 1396d(p)(3)(A)(ii) ) under a State plan under title XIX of that Act ( 42 U.S.C. 1396 et seq.); (4) the term Medicare part B means the Medicare program for supplementary medical insurance benefits under part B of title XVIII of the Social Security Act ( 42 U.S.C. 1395j et seq.); and (5) the term Postal Service annuitant has the meaning given the term in section 8903c(a) of title 5, United States Code, as added by section 101 of this Act. (b) Subsidies With respect to the monthly Medicare part B premium payments of eligible individuals (taking into account any adjustments, including those under subsections (b) and (i) of section 1839 of the Social Security Act ( 42 U.S.C. 1395r )), the Postal Service— (1) in the initial contract year, shall subsidize 75 percent of the Medicare part B premium payments; (2) in the first year after the initial contract year, shall subsidize 50 percent of the Medicare part B premium payments