**Problem**

Have you ever watched the movie *Matrix* ? In that movie, the term *Matrix* does not mean a mathematical thing, but a complicated AI system.

In this problem, we will go back to the original meaning of matrix. Given a 0-1 matrix, you are required to find the maximum submatrix in it which contains only 0s.

**Sample Input**

An integer T (T <= 110) in the first line indicates the number of test case. For each test case, two integers N and M will be given first, then followed by a N * M 0-1 matrix.

1 <= N, M <= 100.

**Sample Output **

For each test case, print the number of elements in the maximum submatrix in a single line.

**Input**

2 2

0 0

0 0

4 5

1 0 1 0 0

0 1 0 0 0

0 0 1 0 0

1 1 0 0 0

**Output**

8