题目描述

Find out how many ways there are to divide the N×M chessboard into several 1×2 rectangles. For example, when N=2, M=4, there are 5 schemes in total. When N=2, M=3, there are 3 schemes.

As shown below:

输入格式

The input contains sets of test cases. Each set of test cases occupies a line and contains two integers N and M. 1≤N, M≤11 When the input use case N=0, M=0, it means that the input is terminated, and the use case does not need to be processed.

输出格式

Each test case outputs a result, and each result occupies one line.

1 2
1 3
1 4
2 2
2 3
2 4
2 11
4 11
0 0

1
0
1
2
3
5
144
51205