func_code_string: #include <bits/stdc++.h>   using namespace std;   unordered_map<int, int> errors;   void get_codes(unordered_map<int, int>& quantity, int cnt, int inc) {     for (int i = 0; i < cnt; i++) {       int code;       cin >> code;       quantity[code] += inc;     }   }   int main() {     ios_base::sync_with_stdio(0);     int bugs;     cin >> bugs;     get_codes(errors, bugs, 1);     get_codes(errors, bugs - 1, -3);     for (auto it = errors.begin(); it != errors.end(); ++it) {       if ((it->second) % 2 != 0) {         cout << (it->first) <<   n ;         (it->second) -= 1;       }     }     get_codes(errors, bugs - 2, 2);     for (auto it = errors.begin(); it != errors.end(); ++it)       if ((it->second) != 0) cout << (it->first) <<   n ;   }   