#include <bits/stdc++.h>
using namespace std;
pair<int, int> operator+(const pair<int, int> &a, const pair<int, int> &b) {
  return make_pair(a.first + b.first, a.second + b.second);
}
pair<int, int> operator-(const pair<int, int> &a, const pair<int, int> &b) {
  return make_pair(a.first - b.first, a.second - b.second);
}
pair<int, int> &operator+=(pair<int, int> &a, const pair<int, int> &b) {
  a.first += b.first;
  a.second += b.second;
  return a;
}
pair<int, int> &operator-=(pair<int, int> &a, const pair<int, int> &b) {
  a.first -= b.first;
  a.second -= b.second;
  return a;
}
template <class T, class U>
bool cmp_second(const pair<T, U> &a, const pair<T, U> &b) {
  return a.second < b.second;
}
template <class T>
T gcd(T a, T b) {
  a = abs(a);
  b = abs(b);
  while (b) {
    T t = b;
    b = a % b;
    a = t;
  }
  return a;
}
template <class T>
pair<T, T> ext_gcd(T a, T b) {
  T a0 = 1, a1 = 0, b0 = 0, b1 = 1;
  if (a < 0) {
    a = -a;
    a0 = -1;
  }
  if (b < 0) {
    b = -b;
    b1 = -1;
  }
  while (b) {
    T t, q = a / b;
    t = b;
    b = a - b * q;
    a = t;
    t = b0;
    b0 = a0 - b0 * q;
    a0 = t;
    t = b1;
    b1 = a1 - b1 * q;
    a1 = t;
  }
  return make_pair(a0, a1);
}
inline int sg(int x) { return x ? (x > 0 ? 1 : -1) : 0; }
int main(void) {
  int len, skip;
  scanf("%d %d", &(len), &(skip));
  len++;
  skip++;
  long long sol = 0;
  for (int a = skip; a <= len - a; a++) {
    int b = len - a;
    int ab3 = a * b * 3;
    int cnt = 0;
    for (int c = skip; c <= len - skip; c++) {
      int dmax = (ab3 - 1) / (a + c) - b;
      dmax = min(dmax, len - skip);
      dmax = max(dmax, skip - 1);
      if (dmax < skip) break;
      cnt += dmax - (skip - 1);
    }
    sol += cnt + (a < len - a ? cnt : 0);
  }
  sol *= 3;
  cout << sol << endl;
  return 0;
}
