import java.io.*;
import java.lang.*;
import java.math.*;
import java.util.*;

import javax.rmi.CORBA.Util;

public class Main {
	int n, k = 0, comps = 0;
	Vektor[] g, bg;
	boolean[] u;
	int[] comp, ls, ind;

	public void solve() throws IOException {
		n = nextInt();
		g = new Vektor[n];
		bg = new Vektor[n];
		for (int i = 0; i < n; i++) {
			g[i] = new Vektor(n);
			bg[i] = new Vektor(n);
		}

		for (int i = 0; i < n; i++) {
			int x = nextInt();
			while (x > 0) {
				g[i].add(x - 1);
				bg[x - 1].add(i);
				x = nextInt();
			}
		}

		u = new boolean[n];
		comp = new int[n];
		ls = new int[n];
		ind = new int[n];

		for (int i = 0; i < n; i++)
			if (!u[i])
				dfs(i);

		Arrays.fill(u, false);
		for (int i = n - 1; i >= 0; i--)
			if (!u[ls[i]])
				col(ls[i], comps++);

		for (int i = 0; i < n; i++)
    		for (int _ = 0, j = g[i].body[_]; _ < g[i].cnt; j = g[i].body[++_])
				if (comp[i] != comp[j]) {
					ind[comp[j]]++;
//					out.println(" >> " + comp[j]);
				}

		int cnt = 0, f = -1;
		for (int i = 0; i < comps; i++)
			if (ind[i] == 0) {
				cnt++; f = i;
			}

		if (cnt == 1)
			for (int i = 0; i < n; i++)
				if (comp[i] == f)
					out.print((i + 1) + " ");

		out.println(0);
	}

	void dfs(int v) {
		u[v] = true;
		for (int _ = 0, to = g[v].body[_]; _ < g[v].cnt; to = g[v].body[++_])
			if (!u[to])
				dfs(to);
		ls[k++] = v;
	}

	void col(int v, int color) {
		u[v] = true;
		comp[v] = color;
//		out.print("color of " + v + " is " + color + "\n");
		for (int _ = 0, to = bg[v].body[_]; _ < bg[v].cnt; to = bg[v].body[++_])
			if (!u[to])
				col(to, color);
	}

	public void run() throws IOException {
		boolean STDIO = true;
		// STDIO = false;
		tok = new StringTokenizer("");
		if (STDIO) {
			in = new BufferedReader(new InputStreamReader(System.in));
			out = new PrintWriter(System.out);
		} else {
			in = new BufferedReader(new FileReader("input.txt"));
			out = new PrintWriter(new File("output.txt"));
		}
		solve();
		out.close();
	}

	public static void main(String[] args) throws IOException {
		new Main().run();
	}

	String nextToken() throws IOException {
		while (!tok.hasMoreTokens())
			tok = new StringTokenizer(in.readLine());
		return tok.nextToken();
	}

	int nextInt() throws IOException {
		return Integer.parseInt(nextToken());
	}

	long nextLong() throws IOException {
		return Long.parseLong(nextToken());
	}

	double nextDouble() throws IOException {
		return Double.parseDouble(nextToken());
	}

	static class Vektor {
	    int[] body;
	    int cnt;

	    Vektor(int size) {
	        body = new int[size];
	        cnt = 0;
	    } // Vektor

	    void add(int v) {
	        body[cnt++] = v;
	    } // add
	} // Vektor


	BufferedReader in;
	StringTokenizer tok;
	PrintWriter out;
}