func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, ai, nb = 0;     map<int, int> dict;     map<int, int>::iterator it;     cin >> n;     int i = 0;     while (i < n) {       cin >> ai;       dict[ai]++;       i++;     }     for (it = dict.begin(); it != dict.end(); it++) {       while ((it->second) > 1) {         it->second = (it->second) - 2;         nb++;       }     }     cout << (nb / 2);     return 0;   }   