#include <bits/stdc++.h>
using namespace std;
int search_around(int k[], int i, int n) {
  int ans = 1;
  for (int j = i - 1; 0 <= j && j <= 1001 * 1001 && k[j] == n; j--) ans++;
  for (int j = i + 1; 0 <= j && j <= 1001 * 1001 && k[j] == n; j++) ans++;
  return ans;
}
int search(int k[], int n) {
  int l = 0, r = 1001 * 1001;
  while (r - l >= 1) {
    int i = (l + r) / 2;
    if (k[i] == n)
      return search_around(k, i, n);
    else if (k[i] < n)
      l = i + 1;
    else
      r = i;
  }
  return 0;
}
int main() {
  int k[1001 * 1001];
  ;
  for (int i = 0; i <= 1000; i++) {
    for (int j = 0; j <= 1000; j++) {
      k[1001 * i + j] = i + j;
    }
  }
  sort(k, k + 1001 * 1001);
  int n;
  while (cin >> n) {
    int ans = 0;
    for (int i = 0; i <= 1000; i++) {
      for (int j = 0; j <= 1000; j++) {
        ans += search(k, n - i - j);
      }
    }
    cout << ans << endl;
  }
}
