Please solve using formula, NOT EXCEL

Mina purchases a 7% 22-year callable bond with face value F that pays semiannual coupons. The bond can be called for par at any coupon date starting at the end of year 18. Mina pays a price of 2661.87, which guarantees her a nominal seminannual yield of at least 5\%. Lucy purchases a 22-year bond identical to the one Mina purchased except it is not callable. If Lucy's bond has a semiannual yield of 5%, how much did she pay for it