#include<bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  vector<vector<int>> E(N);
  for (int i = 0; i < N; i++) {
    int M;
    cin >> M;
    for (int j = 0; j < M; j++) {
      int A;
      cin >> A;
      A--;
      E[i].push_back(A);
    }
  }
  vector<bool> used(N, false);
  queue<int> Q;
  Q.push(0);
  while (!Q.empty()) {
    int v = Q.front();
    used[v] = true;
    Q.pop();
    for (int w : E[v]) {
      if (!used[w]) {
        used[w] = true;
        Q.push(w);
      }
    }
  }
  bool ok = true;
  for (int i = 0; i < N; i++) {
    if (!used[i]) ok = false;
  }
  cout << (ok ? "Yes" : "No") << endl;
}