I Got a Matrix! [Simulation]

Description–

Given an n * m matrix A, interrogation of the matrix and the elements of the edge. The edge of the so-called matrix elements, is the first line and
the elements as well as elements of the last line of the first column and the last column.

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Input–

The first line contains two integers n and m.
After n lines each containing m integers Ai, j.

Output–

Total line contains an integer ans, the edge of the matrix elements represents the sum.

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Sample Input–

3 3
3 4 1
3 7 1
2 0 1

Sample Output–

15

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Notes -

To 100% of the data: n, m ≤ 100

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Code -

#include<iostream>
#include<cstdio>
using namespace std;
int n,m,a[105][105];
long long ans;
int main()
{
	scanf("%d%d",&n,&m);
	for (int i=1;i<=n;++i)
	  for (int j=1;j<=m;++j)
	  {
	  	  scanf("%d",&a[i][j]);
	  	  if (i==1 || i==n || j==1 || j==m) ans+=a[i][j];
	  }
	printf("%lld",ans); 
	
	return 0;
}