# 2127. Paper Cutting

You are given a paper of dimension mn, and you have to cut into mn squares each of dimension 11 using a scissors. What is the minimum number of cuts needs to get all mn squares?

### 输入格式

Input consists of several test cases. Each case appears on a single line, and there is no blank line between two cases. Each line has two numbers m and n, indicating the dimension of the paper. The input is terminated by the case m=0 and n=0. You do not have to handle this case. Both m and n will fit in a 32-bit integer representation.

### 输出格式

For each input, output the minimum number of cuts needed, as specified above.

### 样例

Input
2 2
1 1
5 1
0 0

Output
3
0
4


34 人解决，77 人已尝试。

37 份提交通过，共有 121 份提交。

5.6 EMB 奖励。