#include <stdio.h>
#include <stdlib.h>
#include "graph.c"

void pass(int** matrix, int a, int b, int n, int prev, int *k){
    for (int i = 0; i < n; i++){
        if ((matrix[a][i] == 1) && (i != prev)){
            if (i == b) {
                *k = 1;
            }
            pass(matrix, i, b, n, a, k);
        }
    }
}

int main() {
    int ** matrix;
    int n, a, b;
    int q = 0;
    FILE *f;
    f = fopen ("text.txt", "r");

    fscanf (f, "%d", &n);

    matrix = (int**)malloc(n * sizeof(int*));
    for (int i = 0; i < n; i++) matrix[i] = (int *)malloc(n * sizeof(int));

    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            fscanf (f, "%d", &matrix[i][j]);
        }
    }

    fscanf (f, "%d", &a);
    fscanf (f, "%d", &b);
    pass(matrix, a, b, n - 1, 0, &q);
    if (q == 1) printf("YES\n");
    else printf("NO\n");
    return 0;
}