#include<bits/stdc++.h> namespace { #pragma GCC diagnostic ignored "-Wunused-function" #include<atcoder/all> #pragma GCC diagnostic warning "-Wunused-function" using namespace std; using namespace atcoder; #define rep(i,n) for(int i = 0; i < (int)(n); i++) #define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--) #define all(x) begin(x), end(x) #define rall(x) rbegin(x), rend(x) template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; } template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; } using ll = long long; using P = pair<int,int>; using VI = vector<int>; using VVI = vector<VI>; using VL = vector<ll>; using VVL = vector<VL>; } int main() { ios::sync_with_stdio(false); cin.tie(0); int n; cin >> n; scc_graph g(n); VVI to(n); rep(i, n) { int m; cin >> m; rep(_, m) { int a; cin >> a; a--; g.add_edge(i, a); to[i].emplace_back(a); } } auto scc = g.scc(); int sz = scc.size(); VI cls(n); rep(i, sz) for (int v : scc[i]) cls[v] = i; bool ans = true; rep(i, sz - 1) { bool found = false; for (int u : scc[i]) for (int v : to[u]) if (cls[v] == i + 1) { found = true; } if (!found) { ans = false; break; } } cout << (ans ? "Yes\n" : "No\n"); }