func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> v[10003], v1[10003];   int cnt[10003];   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int n, m, i, j;     cin >> m >> n;     for (i = 0; i < m; i++) {       int x, y;       cin >> x;       memset(cnt, 0, sizeof(cnt));       for (j = 0; j < x; j++) {         cin >> y;         v[i].push_back(y);         cnt[y]++;       }       for (j = 1; j <= n; j++) {         if (!cnt[j]) v1[i].push_back(j);       }       sort(v[i].begin(), v[i].end());       sort(v1[i].begin(), v1[i].end());     }     for (i = 0; i < m; i++)       for (j = 0; j < m; j++) {         int fl = 1;         for (int k = 0; k < v[i].size(); k++) {           if (!binary_search(v1[j].begin(), v1[j].end(), v[i][k])) fl = 0;         }         if (fl) {           cout <<  impossible ;           return 0;         }       }     cout <<  possible ;   }   