View Code of Problem 51

#include<iostream>

using namespace std;

int main()
{
    int n;
    cin>>n;
    int r[n][n],sum=0;
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            cin>>r[i][j];
            if(i>=j)
                sum+=r[i][j];
        }
    }
    cout<<sum;
    return 0;
}