#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int a, b, c, d;
  int count;
  while (cin >> n) {
    count = 0;
    for (a = 0; a <= n && a <= 1000; ++a) {
      if (n - a <= 3000)
        for (b = 0; b <= n - a && b <= 1000; ++b) {
          if (n - a - b <= 2000)
            for (c = 0; c <= n - a - b && c <= 1000; ++c) {
              if (n - a - b - c <= 1000) count++;
            }
        }
    }
    cout << count << endl;
  }
}
