func_code_string: #include <bits/stdc++.h>   const int N = 1000010;   const int inf = 0x3f3f3f3f;   using namespace std;   int n, m;   int c[N];   int main() {     scanf( %d%d , &n, &m);     for (int i = 0; i < m; i++) {       int a, b;       scanf( %d%d , &a, &b);       c[a]++;       c[b]++;     }     if (n < 3) return puts( 0 ), 0;     long long ret = 0;     for (int i = 1; i <= n; i++) ret += 1ll * c[i] * (n - 1 - c[i]);     ret /= 2;     cout << (1ll * n * (n - 1) * (n - 2) / 6 - ret) << endl;     return 0;   }   