#include <algorithm>
#include <bitset>
#include <deque>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <iomanip>
#include <vector>

#define fst first
#define snd second
#define all(x) (x).begin(), (x).end()
#define clr(a, v) memset( a , v , sizeof(a) )
#define pb push_back
#define mp make_pair
#define sz size()
#define FORN( i , s , n ) for( int i = (s) ; i < (n) ; i++ )
#define FOR( i , n ) FORN( i , 0 , n )
#define FORIT( i , x ) for( typeof x.begin() i = x.begin() ; i != x.end() ; i++ )
#define trace(x)    cerr << #x << ": " << x << endl;
#define trace2(x, y) cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define read ios::sync_with_stdio(false)

using namespace std;

typedef long long int64;
typedef vector <int> vi;
typedef pair <int,int> ii;
typedef vector <string> vs;
typedef vector <ii> vii;

vi adj  [2005];

int vis [2005];
int num [2005];
int low [2005];
int comp[2005];

int indegree [2005];
int S[2005];
int ts;
int contn, compcont;

void dfs(int v){
    num[v] = low[v] = contn++;
    vis[v] = 1;
    S[ts++] = v;
    FOR(i,adj[v].sz){
        int u = adj[v][i];
        if ( num[u] == -1 ) dfs(u);
        if ( vis[u] ) low[v] = min(low[v],low[u]);
    }
    if ( low[v] == num[v] ){
        while(1){
            int u = S[ts-1]; ts--;
            comp[u] = compcont;
            vis[u]  = 0;
            if ( u==v ) break;
        }
        compcont++;
    }
}

int main(){
    read;
    int N,v;
    cin>>N;
    FOR(i,N)
        while(cin>>v and v)
            adj[i].pb(v-1);

    contn = compcont = 0;
    FOR(i,N) {vis[i]=0; num[i]=-1;}
    ts = 0;
    FOR(i,N) if (num[i]==-1) dfs(i);
    FOR(i,compcont) indegree[i]=0;

    FOR(i,N)
        FOR(j,adj[i].sz) if ( comp[i]!=comp[adj[i][j]] ) indegree[comp[adj[i][j]]]++;

    int one = 0, SCC =-1;
    FOR(i,compcont) if ( indegree[i]==0 ) {one++;SCC=i;}

    if(one==1)
        FOR(i,N) if ( comp[i]==SCC ) cout<<i+1<<" ";

    cout<<0<<endl;
}