#include <iostream>
#include <vector>
using namespace std;

const int INF = 1e9;

void bfs(vector<vector<int>>& graph, vector<char>& add, vector<int>& dist, int st)
{
    int n = dist.size();
    int vertex = st;
    vector<int> vert;
    vert.push_back(vertex);
    bool ok = true;
    while (ok)
    {
        vector<int> vert2;
        for (int i = 0; i < vert.size(); i++)
        {
            for (int j = 0; j < graph[vert[i]].size(); j++)
            {
                int v = graph[vert[i]][j];
                if (add[v] == false)
                {
                    dist[v] = dist[vert[i]] + 1;
                    add[v] = true;
                    vert2.push_back(v);
                }
            }
        }
        vert = vert2;
        if (vert.size() == 0)
        {
            ok = false;
        }
    }

}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n;
    cin >> n;
    vector<vector<int>> graph0(n, vector<int>(n));
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            cin >> graph0[i][j];
        }
    }
    vector<vector<int>> graph(n);
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (graph0[i][j] == 1)
            {
                graph[i].push_back(j);
            }
        }
    }
    int st, en;
    cin >> st >> en;
    st--;
    en--;
    vector<char> add(n, false);
    vector<int> dist(n, INF);
    add[st] = true;
    dist[st] = 0;
    bfs(graph, add, dist, st);
    if (dist[en] != INF)
    {
        cout << dist[en] << '\n';
        if (dist[en] != 0)
        {
            int vertex = en;
            vector<int> way;
            way.push_back(vertex);
            while (vertex != st)
            {
                for (int i = 0; i < graph[vertex].size(); i++)
                {
                    if (dist[graph[vertex][i]] == dist[vertex] - 1)
                    {
                        vertex = graph[vertex][i];
                        way.push_back(vertex);
                    }
                }
            }
            for (int i = way.size() - 1; i >= 0; i--)
            {
                cout << way[i] + 1 << ' ';
            }
        }
    }
    else
    {
        cout << -1 << '\n';
    }
}