#include <bits/stdc++.h>
using namespace std;

vector<vector<int>> g;
vector<int> group, hate_cnt;
set<int> hate_set[4];

void update(int x, int cnt) {
    hate_set[hate_cnt[x]].erase(x);
    hate_cnt[x] = cnt;
    hate_set[cnt].insert(x);
}

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    g.resize(n + 1); group.resize(n + 1); hate_cnt.resize(n + 1);
    for (int i = 1; i <= n; i++) {
        int x, cnt1 = 0;
        for (cin >> x; x != 0; cin >> x) {
            g[i].push_back(x);
            cnt1 += group[x];
        }
        if (cnt1 * 2 < g[i].size()) {
            group[i] = 1;
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int x : g[i])
            hate_cnt[i] += (group[x] == group[i]);
        hate_set[hate_cnt[i]].insert(i);
    }
    while (hate_set[3].size() > 0 || hate_set[2].size() > 0) {
        int p = hate_set[3].size() > 0 ? *hate_set[3].begin() : *hate_set[2].begin();
        group[p] = 1 - group[p];
        update(p, g[p].size() - hate_cnt[p]);
        for (int x : g[p])
            update(x, group[x] == group[p] ? hate_cnt[x] + 1 : hate_cnt[x] - 1);
    }
    cout << count(group.begin() + 1, group.end(), 0) << endl;
    for (int i = 1; i <= n; i++)
        if (group[i] == 0)
            cout << i << " ";
    cout << endl;
    return 0;
}