#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define each(e, v) for(auto &e: v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

struct io_setup{
    io_setup(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

struct Graph{
    vector<vector<int>> es;
    const int n;

    Graph(int n) : n(n){
        es.resize(n);
    }

    void add_edge(int from, int to, bool directed = true){
        es[from].pb(to);
        if(!directed) es[to].pb(from);
    }
};

struct Strongly_Connected_Components{
    vector<vector<int>> es, rs;
    vector<int> vs, comp;
    vector<bool> used;
    const int n;

    Strongly_Connected_Components(int n) : n(n){
        es.resize(n), rs.resize(n);
        vs.resize(n), comp.resize(n), used.resize(n);
    }

    void add_edge(int from, int to, bool directed = true){
        es[from].pb(to), rs[to].pb(from);
        if(!directed) es[to].pb(from), rs[from].pb(to);
    }

    void topological_sort(int now){
        used[now] = true;
        each(e, es[now]) if(!used[e]) topological_sort(e);
        vs.pb(now);
    }

    void track_back(int now, int cnt){
        used[now] = true, comp[now] = cnt;
        each(e, rs[now]) if(!used[e]) track_back(e, cnt);
    }

    Graph decompose(){
        fill(all(used), false);
        rep(i, n) if(!used[i]) topological_sort(i);
        fill(all(used), false), reverse(all(vs));
        int cnt = 0;
        each(e, vs) if(!used[e]) track_back(e, cnt++);
        Graph G(cnt);
        rep(i, n){
            each(e, es[i]){
                int u = comp[i], v = comp[e];
                if(u != v) G.add_edge(u, v, true);
            }
        }
        return G;
    }

    int operator [] (int k) const {return comp[k];}
};

int main(){
    int N; cin >> N;

    vector<int> d(N);
    vector<vector<int>> S(N);

    int MAX = 2000;

    Strongly_Connected_Components scc(MAX);

    rep(i, N){
        cin >> d[i];
        S[i].resize(d[i]);
        rep(j, d[i]) cin >> S[i][j];
        scc.add_edge(S[i][0], S[i][d[i]-1], true);
    }

    if(scc.decompose().n != MAX) {cout << "0\n"; return 0;}

    vector<int> ans(MAX);
    rep(i, MAX) ans[scc[i]] = i;
    cout << MAX << '\n';
    rep(i, MAX){
        cout << ans[i];
        cout << (i == MAX-1? '\n' : ' ');
    }
}