# Find the perfect land of C shape

Debasis is searching for a **perfect land to build a new house**. There is an area of size **N*M** and each point of **N*M** has a value. But he wants exactly a **land of size 3*3 but the land should be perfect**.

A **perfect land is a land whose 'C' shape value is maximum**.

You being his friend, help him to find the perfect land.

**Input**

First line of the input is two space separated integer **N** and **M**

Second line of the input contains the matrix of size **N*M** (**N** rows **M** columns).

**Output**

A single integer containing the sum of the perfect land.

**Example:**

Input:
6 6
0 0 1 1 1 0
0 0 1 0 0 0
0 0 1 1 1 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
Output:
7

Here is

the perfect land whose sum value is maximum.Note:Before going to solution please try it by yourself.C++ implementation:

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