矩阵归零

Problem Description

There is a matrix with m rows and n columns. An element of the matrix has at most four adjacent elments(up, down,left,right). You can add a same number to a pair of adjacent elements of the matrix. By doing this operation repeation repeatly, can you make the matrix zero?

Input

A line contains m and n indicating the rows and columns of the matrix. (0<m,n<5)
Each of the following m lines contains n integers(-10^6<=each integer<=10^6)
Input is terminated by one line contains two zeros.

Output

if the matrix can be converted into zero, ouput"Yes" on a line otherwise output "No" on a line.

Sample Input

2 21 11 02 20 01 10 0

Sample Output

NoYes

Author

HYNU 

代码：