Wishingbone has a new house of which the floor needs to be coverd by ceramic tiles. A ceramic tile shapes like the letter 'L'. Now Wishingbone wants to know whether the floor can be fully coverd by sufficiently many tiles.
Figure 1 illustrates a tile. Figure 2 shows how the floor with size 2 * 4 be coverd by 2 tiles.
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Figure 1 Figure 2
Input
Input consists of several cases, each occupies one line that contains 2 positive integers m and n, which describe the sizes of the floor.
Output
For each case, if the floor can be fully coverd by tiles output "Yes" in a line; else output the least spaces that can not be coverd.
Sample Input
1 3
2 3
2 4
Sample Output
3
2
Yes
http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=2028