elow is a cash flow projection on a sequential$-$pay CMO, which has four tranches, A through D$.$ Assume the four tranches get paid in the order of A$->$B$->$C$->$D$.$ In this month tranche A has an outstanding balance of $62,000$ and B has an outstanding balance of $31,000.$ What is the principal payment towards tranche B in this month?

Enter your answer in thousands of dollars, with no decimals. For example, if your answer is $$40,000,$ then enter $40.$

month beginning balance scheduled principal payment Prepayment Interest to MBS investors

$33$ $$615,00028,00013,00056,000$