func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 1e9;   const long long INFLL = 1e18 + 1;   const int MAX = 200001;   const long long MOD = 1000000007;   long long inq(long long k, long long q) {     if (q == 0) return 1;     long long l = inq(k, q / 2);     if (q % 2 == 0)       return l * l % MOD;     else       return (l * l) % MOD * k % MOD;   }   long long gcd(long long a, long long b) {     if (a < b) swap(a, b);     if (b == 0) return a;     return gcd(b, a % b);   }   long long cubr(long long a) {     long long l = -1, r = 1e6 + 2;     while (l < r - 1) {       long long mid = (l + r) / 2;       if (mid * mid * mid > a)         r = mid;       else         l = mid;     }     return l;   }   long long max(long long a, long long b) {     if (a > b) return a;     return b;   }   long long min(long long a, long long b) { return -1 * max(-a, -b); }   long long possible(long long q) {     if (q == INF) return -1;     return q;   }   bool correct(int x, int xx) {     if (x < 0) return 0;     if (x >= xx) return 0;     return 1;   }   long long dsumm(long long x, long long k) {     long long y = 1;     long long z = 0;     for (int i = 0; y < 1e18; i++) {       z += x / y % k;       y *= k;     }     return z;   }   long long dcount(long long x) {     long long y = 1;     long long z = 0;     int c[100];     for (int i = 0; i < 10; i++) c[i] = 0;     for (int i = 0; x > 0; i++) {       if (c[x / y % 10] == 0) z++;       c[x / y % 10] = 1;       x /= 10;     }     return z;   }   long long lg10(long long x) {     if (x == 0) return 0;     return lg10(x / 10) + 1;   }   long long n, m;   vector<int> graph[4000], graph2[4000];   long long ans;   long long d[5000];   long long f[4000];   long long ff[4000];   int main() {     cin >> n >> m;     for (int(i) = 0; (i) != (m); i++) {       int x, y;       cin >> x >> y;       x--;       y--;       graph[x].push_back(y);       graph2[y].push_back(x);     }     long long it = 2;     for (int b = 0; b < n; b++) {       for (int c = b + 1; c < n; c++) {         long long x = 0;         long long y = 0;         long long z = 0;         for (int i = 0; i < graph[b].size(); i++) {           d[graph[b][i]] = it;         }         for (int i = 0; i < graph[c].size(); i++) {           if (d[graph[c][i]] == it) {             x++;           }         }         it++;         for (int i = 0; i < graph2[b].size(); i++) {           d[graph2[b][i]] = it;         }         for (int i = 0; i < graph2[c].size(); i++) {           if (d[graph2[c][i]] == it) {             y++;           }         }         it++;         for (int i = 0; i < graph[b].size(); i++) {           ff[graph[b][i]] = it * 7;         }         for (int i = 0; i < graph[c].size(); i++) {           if (ff[graph[c][i]] == it * 7)             ff[graph[c][i]]++;           else             ff[graph[c][i]] = 0;         }         for (int i = 0; i < graph2[b].size(); i++) {           if (ff[graph2[b][i]] == it * 7 + 1)             ff[graph2[b][i]]++;           else             ff[graph2[b][i]] = 0;         }         for (int i = 0; i < graph2[c].size(); i++) {           if (ff[graph2[c][i]] == it * 7 + 2) {             z++;             ff[graph2[c][i]] = 0;           }         }         ans += (x - z) * (y - z) + z * (z - 1) + z * (x - z) + z * (y - z);       }     }     cout << ans;   }   