Given a 2D matrix, the task is to find maximum sum of a hour glass.

An hour glass is made of 7 cells
in following form.
    A B C
      D
    E F G

Examples:

Input : 1 1 1 0 0 
        0 1 0 0 0 
        1 1 3 0 0 
        0 0 0 2 0 
        0 0 0 0 4 
Output : 9
Below is the hour glass with
maximum sum:
3 0 0 
  2
0 0 4

Input:
The first line of input contains an integer T denoting the no of test cases. Then T test cases follow. Each test case contains two space separated integers N and M denoting the size of the matrix. Then in the next line are N*M values of the matrix (m).

Output:
For each test case in a new line print the required output.

Constraints:
1<=T<=100
1<=N,M<=20 
1<=m[][]<1000

Example:
Input:
2
1 2
1 2 
3 3 
1 1 1 1 1 1 1 1 1 

Output:
-1
7

** For More Input/Output Examples Use 'Expected Output' option **