PMT(rate,nper,pv[,fv,type])
PMT returns the amount of payment for a loan based on a constant interest rate and constant payments (each payment is equal amount).
rate is the constant interest rate.
nper is the overall number of payments.
pv is the present value.
fv is the future value.
type is the type of the payment: 0 means at the end of the period and 1 means at the beginning of the period.