160

import java.util.LinkedList;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        byte[][] graph = new byte[n][n];

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                graph[i][j] = in.nextByte();
            }
        }

        int start = in.nextInt() - 1;
        int finish = in.nextInt() - 1;
        int[] way = new int[n];
        for (int i = 0; i < n; i++)
            way[i] = -1;
        way[start] = -1;
        boolean[] used = new boolean[n];
        LinkedList<Integer> q = new LinkedList<>();
        q.add(start);
        boolean yes = true;
        while (!q.isEmpty()) {
            int x = q.pollFirst();
            for (int i = 0; i < n; i++) {
                if (graph[x][i] == 1 && !used[i]) {
                    q.addLast(i);
                    way[i] = x;
                    used[i] = true;
                }
            }
        }

        int f = 0;
        while (finish != start && f < n + 2) {
            q.addFirst(finish);
            if (way[finish] >= 0)
                finish = way[finish];
            f++;
        }
        if (f == n + 2)
            System.out.println(-1);
        else {
            System.out.println(q.size());
            if (q.size() != 0) {
            System.out.print(start+1);
            while (!q.isEmpty()) {
                System.out.print(" " + (q.pollFirst() + 1));
            }
            }
        }
    }
}