#include <iostream>
using namespace std;
int main() {
    int arr[3][3] = {{2,4,6},{3,5,7},{1,8,9}};
    int sum = 0;
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            if (i == j) {
                sum += arr[i][j];
            }
        }
    }
    cout << sum << endl;
    return 0;
}