A $20,000 loan with interest at 3.5% is being repaid by 35 level annual payments, the firs one due one year hence. Beginning with the 17th payment, the borrower is permitted to pay one-third the normal annual payment. After the 12th reduced payment, the loan is renegotiated. The revised level payment P will yield the lender 4% per year over the remaining 7 years. Find P.