#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int m;     cin >> m;     set<int> q;     for (int i = 0; i < n; ++i) {       int k;       cin >> k;       for (int j = 0; j < k; ++j) {         int x;         cin >> x;         q.insert(x);       }     }     cout << ((q.size() == m) ?  YES  :  NO ) << endl;     return 0;   }   