View Code of Problem 51

#include<stdio.h>
#include<cstdlib>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
typedef long long ll;
int main(){
    int n,sum=0;
    int a[20][20];
    scanf("%d", &n);
	for(int i=0;i<n;i++){
	for(int j=0;j<n;j++){
	cin>>a[i][j]; 
	} 
	}
	for(int i=0;i<n;i++){
	for(int j=0;j<=i;j++){
	sum=sum+a[i][j];
	}
	}
	printf("%d\n",sum);
	
    
   	  return 0;
}