func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int n, h, g;     vector<int> home, guest;     cin >> n;     while (n--) {       cin >> h >> g;       home.push_back(h);       guest.push_back(g);     }     n = home.size();     h = 0;     for (int i = 0; i < n; i++) {       for (int j = 0; j < n; j++) {         if (home[i] == guest[j]) h++;       }     }     cout << h <<   n ;     return 0;   }   