func_code_string: #include <bits/stdc++.h>   using namespace std;   long long i, n, m, a[1000001], t1, t2, sum;   int main() {     cin >> n >> m;     for (i = 0; i < m; i++) {       scanf( %I64d %I64d , &t1, &t2);       a[t1]++;       a[t2]++;     }     for (i = 1; i <= n; i++) sum += a[i] * (n - 1LL - a[i]);     sum /= 2LL;     cout << n * (n - 1LL) * (n - 2LL) / 6LL - sum << endl;   }   