Solve the programming task below in a Python markdown code block.
Given a matrix you need to find the submatrix with the largest number of elements, where the GCD (Greatest Common Divisor) of its elements is greater than one. A submatrix of the matrix is a sub-section composed of contiguous rows and columns of the original matrix.

Input
Two numbers n,m in the first line. Followed by n lines with m numbers in each line.

Constraints  

1<=N,M<=200

1<=numbers<=10000

Output
Just a largest area where GCD is greater than 1.

Sample Input  

3 3
2 6 8
4 8 3
6 9 4

Sample Output  

4

If you observe the following submatrix:  

2 6  
4 8  

The GCD is 2.
There is no matrix larger than this with a GCD > 1.