View Code of Problem 51

#include<iostream>
#include<algorithm>
#include<math.h>
using namespace std;
int main() {
	int n,sum=0,num;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<n;j++)
		{
			cin>>num;
			if(j<=i)
			sum+=num; 
		}
	}
	cout<<sum;
	return 0;
}