A sequential pay CMO(A:$24 million, B:$16 million, and accural Z:$10 million) is created from a $50 million passthrough (original maturity 30 years) with a WAC of 8.50%, a servicing fee of 1.60% and a WAM of 8 months. The coupon rates for the three tranches are:(A4.90%, B:4.60% and Z:4.00%) The collateral scheduled principal repayment for month 1 is $7 million. What is the total principal payment to tranche A in month 1 at 100 PSA?