#include 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; using pil = pair; using pli = pair; using pll = pair; const int MOD = 1000000007; //const int MOD = 998244353; const int inf = (1<<30)-1; const ll INF = (1LL<<60)-1; template bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;}; template 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> 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> es, rs; vector vs, comp; vector 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 d(N); vector> 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].front(), S[i].back(), true); } if(scc.decompose().n < MAX) {cout << "0\n"; return 0;} vector ans(MAX); rep(i, MAX) ans[scc[i]] = i; cout << MAX << '\n'; rep(i, MAX) cout << ans[i] << ' '; cout << '\n'; }