func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       bool impr = false;       bool taken[n + 1];       for (int i = 0; i <= n; i++) {         taken[i] = false;       }       int notTaken = -1;       for (int i = 0; i < n; i++) {         int k;         cin >> k;         bool done = false;         for (int i = 0; i < k; i++) {           int next;           cin >> next;           if (!done && !taken[next]) {             taken[next] = true;             done = true;           }         }         if (!done) {           impr = true;           notTaken = i + 1;         }       }       if (impr) {         cout <<  IMPROVE  << endl;         int good = 0;         for (int i = 1; i <= n; i++) {           if (taken[i] == false) {             good = i;           }         }         cout << notTaken <<     << good << endl;       } else {         cout <<  OPTIMAL  << endl;       }     }   }   