func_code_string: #include <bits/stdc++.h>   using namespace std;   long long nMod = 1e9 + 7;   inline long long GCD(long long a, long long b) {     while (b != 0) {       long long c = a % b;       a = b;       b = c;     }     return a;   };   inline long long LCM(long long a, long long b) { return (a / GCD(a, b)) * b; };   int m, n, k;   vector<set<int>> st(55);   void vietnakid() {     cin >> m >> n;     for (int i = 0; i < m; i++) {       cin >> k;       for (int j = 0; j < k; j++) {         int x;         cin >> x;         st[i].insert(x);       }     }     bool check = true;     for (int i = 0; i < m; i++) {       if (!check) break;       for (int j = 0; j < m; j++) {         bool ok = false;         for (auto x : st[i]) {           if (ok) break;           if (st[j].count(x)) {             ok = true;           }         }         if (!ok) {           check = false;           break;         }       }     }     if (check) {       cout <<  possible n ;     } else {       cout <<  impossible n ;     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie();     vietnakid();     cerr <<   nTime elapsed:   << 1000 * clock() / CLOCKS_PER_SEC <<  ms n ;     return 0;   }   