func_code_string: #include <bits/stdc++.h>   using namespace std;   int d[1000001] = {0};   int main() {     int n, m;     scanf( %d%d , &n, &m);     for (int i = 0, a, b; i < m; ++i) scanf( %d%d , &a, &b), d[a]++, d[b]++;     long long ans = 0;     for (int i = 1; i <= n; ++i) {       long long de = d[i], ade = n - 1 - de;       ans += de * (de - 1) + ade * (ade - 1) - de * ade;     }     cout << ans / 6 << endl;     return 0;   }   