Advika bought a cadbaury gems pocket for his friends. She opened the pocket and arranged the gems colour wise. After finishing the arrangement it looked like a matrix.

Now She wanted to calculate sum of boundary elements of a matrix.

If you help Advika, she will share chocolates with you.

**Input:**
The first input has two numbers r and c respectively.
Then r rows with c columns follow
**Output:**
print the single value representing sum of boundary elements of a Matrix.

#include <stdio.h> int main() { int r,c; int arr[100][100],sum = 0,i,j; scanf("%d %d",&r,&c); for(i = 0;i < r;i++){ for(j=0;j < c;j++){ scanf("%d",&arr[i][j]); } } for(i=0;i<r;i++){ for(j=0;j<c;j++){ if(i==0 || j==0 || i==r-1 || j==c-1){ sum+=arr[i][j]; } } } //printf("Sum: "); printf("%d",sum); return 0; }

**INPUT_1:**

3 3

1 2 3

4 5 6

7 8 9

**OUTPUT:**

40

**INPUT_2:**

2 3

1 2 3

4 5 4

**OUTPUT:**

19

**INPUT_3:**

3 3

100 200 300

50 26 80

600 120 45

**OUTPUT:**

Sum: 1495

**ILLUSTRATION:**