21688_Cover

Tom wants to cover a rectangular floor by identical L-shape tiles without overlap. As shown below, the floor can be split into many small squares, and the L-shape tile consists of exactly four small squares. The floor of 3×8 can be completely covered by 6 L-shape tiles, but the floor of 3×7 is impossible.

Tom would like to know whether an arbitrary floor with n×m small squares can be completely covered or not. He is sure that when n and m are small he can find the answer by paper work, but when it comes to larger n and m, he has no idea to find the answer. Can you tell him?

The input file will consist of several test cases. Each case consists of a single line with two positive integers m and n ( 1 ≤ m ≤ 15, 1 ≤ n ≤ 40 ).

The input is ended by m=n=0.

For each case, print the word 'YES' in a single line if it is possible to cover the m×n floor, print 'NO' otherwise.

3 8
3 7
0 0

YES
NO