func_code_string: #include <bits/stdc++.h>   using namespace std;   int dx[] = {0, 0, -1, 1};   int dy[] = {-1, 1, 0, 0};   const int N = 1e6 + 5;   long long ans, sum, d[N];   int n, m;   int main() {     int a, b;     while (~scanf( %d%d , &n, &m)) {       memset(d, 0, sizeof(d));       for (int i = 0; i < (m); ++i) {         scanf( %d%d , &a, &b);         d[a]++, d[b]++;       }       if (n < 3) {         puts( 0 );         continue;       }       ans = (long long)n * (n - 1) * (n - 2) / 6;       sum = 0;       for (int i = (1); i <= (n); ++i) sum += d[i] * (n - 1 - d[i]);       sum /= 2;       printf( %lld n , ans - sum);     }     return 0;   }   