Mr. Andre has a debt that will be repaid in 500 installments at the end of each year for 15 years. Mr. Budi has a debt that will be repaid in 500 installments at the end of each year for 10 years. Mr. Andre's remaining debt at the end of the 10th year is 1980.67. Mr. Budi's remaining debt at the end of the 6th year is 1645.06. If the effective interest rates for both debts are the same, determine the principal portion of Mr. Budi's installments on the 10th payment.