#include <iostream>
using namespace std;
int main() {
    int arr[3][3] = {{1,2},{3,4,5},{6}};
    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;
}