View Code of Problem 51

#include<bits/stdc++.h>
using namespace std;

int main()
{
    int a;
    cin >> a;
    int s[10][10];
    for (int i = 0; i < a; i++) {
	   for (int j = 0; j < a; j++) {
		  cin >> s[i][j];
	   }
    }



    int x = 1;
    int sum = 0;
    for (int i = 0; i < a; i++) {
	   for (int j = 0; j < x; j++) {
		  sum += s[i][j];
	   }
	   x++;
    }
    cout << sum << endl;
    return 0;
}