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

int main() {
	int n;
	cin >> n;
	
	vector<vector<int>> M(n, vector<int>(n));
	
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			cin >> M[i][j];
		}
	}
	int u, v;
	cin >> u >> v;
	u--;
	v--;
	
	vector<int> colors(n);
	vector<int> parents(n);
	queue<int> q;
	q.push(u);
	colors[u] = 1;
	parents[u] = u;
	
	while (q.size() > 0) {
		int t = q.front();
		q.pop();
		colors[t] = 2;
		for (int j = 0; j < n; j++) {
			if (M[t][j] == 1 && colors[j] == 0) {
				q.push(j);
				colors[j] = 1;
				parents[j] = t;
			}
		}
	}
	
	if (colors[v] == 0) {
		cout << -1;
		return 0;
	}
	
	stack<int> path;
	path.push(v);
	int t = v;
	while (t != u) {
		t = parents[t];
		path.push(t);
	}
	
	cout << path.size() - 1 << '\n';
	
	if (path.size() > 1) {
		while (path.size() > 0) {
			cout << path.top() + 1 << ' ';
			path.pop();
		}
	}
	
	return 0;
}