View Code of Problem 51

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scanner=new Scanner(System.in);
		int n=scanner.nextInt();
		int[][] ints=new int[n][n];
		for(int i=0;i<n;i++) {
			for(int j=0;j<n;j++) {
				ints[i][j]=scanner.nextInt();
			}
		}
		int sum=0;
		for(int i=0;i<n;i++) {
			for(int j=0;j<=i;j++) {
				sum+=ints[i][j];
			}
		}
		System.out.println(sum);
	}

}