Simon takes out a loan of 10,000. He pays down the interest on the loan at the end of each year and simultaneously makes level payments into a sinking fund. The sinking fund is designed to pay off the loan in 20 years at its 7% effective annual interest rate. Immediately after the fifth payment, the yield on the sinking fund increases to 8% (annual effective rate). Simon therefore adjusts his sinking fund payment to X so that the sinking fund will still accumulate to exactly 10,000, 20 years after the original loan date. Determine X