B

#include <iostream>

int main() {
    int a;
    std::cin>>a;
    int map[a][a];


    for (int x = 0; x < a; x++)
        for (int y = 0; y < a; y++)
            std::cin>>map[x][y];

    for (int x = 0; x < a; x++)
        for (int y = 0; y < a; y++)
            if (x == y && map[x][y] != 0) {
                std::cout<<"YES";
                return 0;
            }

    std::cout<<"NO";
    return 0;
}