func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       bool usa[n], usb[n];       for (int i = 0; i < n; ++i) {         usa[i] = 1;         usb[i] = 1;       }       for (int i = 0; i < n; ++i) {         int a;         cin >> a;         bool f = 1;         for (int j = 0; j < a; j++) {           int b;           cin >> b;           if (usb[b - 1] && f) {             usb[b - 1] = 0;             usa[i] = 0;             f = 0;           }         }       }       bool c = 0, d = 0;       int x, y;       for (int i = 0; i < n; ++i) {         if (usa[i] && !c) {           x = i + 1;           c = 1;         }         if (usb[i] && !d) {           y = i + 1;           d = 1;         }       }       if (c)         cout <<  IMPROVE  << endl << x <<     << y << endl;       else         cout <<  OPTIMAL  << endl;     }   }   