10 years ago, the City of Melrose issued $3,000,000 of 8% coupon, 30-year, semiannual payment, tax-exempt muni bonds. The bonds had 10 years of call protection, but now the bonds can be called if the city chooses to do so. The call premium would be 6% of the face amount. New 20-year, 6%, semiannual payment bonds can be sold at par, but flotation costs on this issue would be 2% of the amount of bonds sold. What is the net present value of the refunding? Note that cities pay no income taxes, hence taxes are not relevant.

(I already culculate the saving per six month, but I don't know how to get the answer 693,443. Would you mind tell me the number for N I/Y PV PMT FV )