func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     scanf( %d %d , &n, &m), ++n;     long long ans = 0;     for (int a = m + 1; a <= n / 2; ++a) {       int tmp = 0;       for (int b = m + 1, c = n - m - 1; b < n - m && c > m; ++b) {         while (c > m && a * ((a << 1) + b - (n << 1) - c) >= -c * (n + b)) --c;         tmp += c - m;       }       if (a != n - a) tmp *= 2;       ans += tmp;     }     cout << ans * 3 << endl;   }   