Please show the steps how to calculate!

Five years ago, the State of Ohio issued $2,000,000 of 7% coupon, 20-year semiannual payment, tax-exempt bonds. The bonds had 5 years of call protection, but now the state can call the bonds if it chooses to do so. The call premium would be 5% of the face amount. Today 15-year, 5%, semiannual payment bonds can be sold at par, but flotation costs on this issue would be 2%. Note that because these are tax-exempt bonds, taxes are not relevant. What is the NPV of the refunding operation