#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <fstream>
#include <stack>
#include <map>
#include <cstring>
#include <cmath>
#include <set>
#include <iterator>
#include <cmath>
#include <locale>
#include <queue>
#include <deque>
#include <stack>


using namespace std;



const int MOD = 1000000000;

void VIVOD(vector<vector<int> > vec2, int n, int m)
{
    for (auto i = 0; i < n; ++i)
    {
        for (auto j = 0; j < m; ++j)
        {
            cout << vec2[i][j] << " ";
        }
        cout << endl;
    }
}

void VIVOD1(vector<int> vec)
{
    for (auto el : vec)
    {
        cout << el << " ";
    }
}
void VIVODq(queue<int> que)
{
    queue<int> q2 = que;
    while (!q2.empty())
    {
        int a = q2.front();
        q2.pop();
        cout << a << " ";
    }
    cout << endl;
}


int main()
{
    /*
    int n, a, m;
    cin >> n;
    vector<int> vec;

    for (auto i = 0; i < n; i++) {
        cin >> a;
        vec.push_back(a);
    }

    cin >> m;
    vector<int> vec2(m + 1, MOD), vec3(m + 1);
    vec2[0] = 0;

    for (auto j = 1; j < m + 1; j++) {

        for (auto i = 0; i < n; i++)

            if (j - vec[i] >= 0 && vec2[j - vec[i]] < vec2[j]) {
                vec2[j] = vec2[j - vec[i]];
                vec3[j] = vec[i];
            }

        vec2[j]++;
    }

    if (vec2[m] >= MOD)
        cout << "No solution";
    else
        while (m > 0) {
            cout << vec3[m] << ' ';
            m -= vec3[m];
        }
    */
    int N, p, w, b;
    queue<int> que;
    cin >> N;
    vector<vector<int > > vec2(N, vector<int>(N));
    vector<int> vec(N), answ;
    for (auto i = 0; i < N; ++i)
    {
        vec[i] = MOD;
        for (auto j = 0; j < N; ++j)
            cin >> vec2[i][j];
    }
    cin >> w >> p;
    vec[w - 1] = 0;
    que.push(w - 1);
  //  VIVOD1(vec, N);
    while (!que.empty()) {
       // cout << endl;
      //  VIVODq(que);
        answ.push_back(que.front() + 1);
      //  cout << endl;
        b = que.front();
        que.pop();
        for (auto j = 0; j < N; ++j)
            if (vec2[b][j] && vec[j] > vec[b] + 1) {
                vec[j] = vec[b] + 1;
                que.push(j);
            }
    }
  //  VIVOD1(vec, N);
 //   VIVOD(vec2, N, N);
    if (vec[p - 1] < MOD) {
        cout << vec[p - 1] << endl;
        if (vec[p - 1] != 0)
            VIVOD1(answ);
    }
    else
        cout << -1;

    return 0;
}

/*
5
0 1 0 0 1
1 0 1 0 0
0 1 0 0 0
0 0 0 0 0
1 0 0 0 0
3 5





*/