; or (iii) a Federal firefighter described in section 8331(21) or 8401(14) of title 5, United States Code. (B) Qualified first responder The term qualified first responder means a first responder who is separated from service due to retirement or disability. (b) Enrollment and coverage periods (1) In general The Secretary shall establish enrollment and coverage periods for individuals who enroll under this section. (2) Coordination Such periods shall be established in coordination with the enrollment and coverage periods for plans offered under an Exchange established under title I of the Patient Protection and Affordable Care Act and plans under parts C and D. If the Secretary determines appropriate, the Secretary may expand such enrollment periods beyond the enrollment periods under such an Exchange or under parts C and D. (3) Beginning of coverage and special enrollment periods The Secretary shall establish such periods so that coverage under this section shall first begin on January 1 of the first year beginning at least one year after the date of the enactment of this section and shall include special enrollment periods, in accordance with section 155.420 of title 45 of the Code of Federal Regulations, that are applicable to qualified health plans offered through an Exchange. (c) Premium (1) Amount of monthly premiums The Secretary shall (beginning for the first year that begins more than 1 year after the date of enactment of this section) determine a monthly premium for all individuals enrolled under this section. Such monthly premium shall be equal to 1⁄12 of the annual premium computed under paragraph (2)(B), which shall apply with respect to coverage provided under this section for any month in the succeeding year. (2) Annual premium (A) Combined per capita average for all medicare benefits The Secretary shall estimate the average, annual per capita amount for benefits and administrative expenses that will be payable under parts A, B, and D (including, as applicable, under part C) in the year for all