27.99

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