The contest’s message distribution is a big thing in prepare. Assuming N students stand in a row, from the row-head start transmit message, each person can transmit message to behind M personals, and how many ways could row-tail get the message?
Input may contain multiple test cases. Each case contains N and M in one line. (0<=M<N<=30) When N=0 and M=0, terminates the input and this test case is not to be processed.