func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2000000 + 10;   int a[N], b[N];   int n, m;   int main() {     int x, y;     scanf( %d%d , &n, &m);     {       for (int i = 0; i < m; i++) {         scanf( %d%d , &x, &y);         x--;         y--;         a[x]++;         a[y]++;       }       for (int i = 0; i < n; i++) b[i] = n - 1 - a[i];       long long total = 0;       for (int i = 0; i < n; i++) total += (long long)a[i] * b[i];       total /= 2;       cout << (long long)n * (n - 1) / 2 * (n - 2) / 3 - total << endl;     }     return 0;   }   