Challenge: Diagonal Sum

Lab C Intermediate 20 points

Read n and then an n × n grid of numbers (row by row). Print the sum of the main diagonal (top-left to bottom-right).

Input

n (1 ≤ n ≤ 10), then n lines of n integers.

Output

The diagonal sum.

Example

Input

Output

Sample input available Sample output available

Editor

Hints

Read the grid with two nested loops.

Diagonal cells have the same row and column: grid[i][i].

Solution explanation

On the main diagonal the row index equals the column index, so one loop is enough to add them up.

Show solution

#include <stdio.h>

int main() {
    int n;
    int grid[10][10];
    scanf("%d", &n);
    for (int r = 0; r < n; r++) {
        for (int c = 0; c < n; c++) {
            scanf("%d", &grid[r][c]);
        }
    }
    int sum = 0;
    for (int i = 0; i < n; i++) {
        sum += grid[i][i];
    }
    printf("%d\n", sum);
    return 0;
}

Output

Answer