func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> vv[3001];   int graf[3001][3001];   int main() {     int n, m;     cin >> n >> m;     for (int i = 0; i < m; i++) {       int f, t;       cin >> f >> t;       vv[f].push_back(t);       graf[f][t] = 1;     }     long long ans(0);     for (int a = 1; a <= n; a++)       for (int c = 1; c <= n; c++) {         if (a == c) continue;         int cnt(0);         for (int i = 0; i < vv[a].size(); i++) {           int b = vv[a][i];           if (graf[b][c]) {             cnt++;           }         }         ans += 1LL * cnt * (cnt - 1) / 2;       }     cout << ans;   }   