#include <bits/stdc++.h>
using namespace std;
long long a, b, c, k;
long long Check_(long long aa, long long bb, long long cc, long long d) {
  if (aa < bb + cc) return 0;
  long long gt = min(d, aa - bb - cc);
  return (gt + 1) * (gt + 2) / 2;
}
int main() {
  ios_base::sync_with_stdio(false);
  long long a, b, c, k;
  cin >> a >> b >> c >> k;
  long long ans = (k + 1) * (k + 2) * (k + 3) / 6;
  for (int i = 0; i <= k; i++)
    ans -= (Check_(a + i, b, c, k - i) + Check_(b + i, a, c, k - i) +
            Check_(c + i, a, b, k - i));
  cout << ans;
  return 0;
}
