#include <bits/stdc++.h>
using namespace std;
int n, s;
int count = 0;
int dp[4001][4];
long long int solve(int i, int j);
int main(void) {
  while (cin >> n) {
    fill_n(*dp, 4001 * 4, -1);
    cout << solve(0, 0) << endl;
  }
}
long long int solve(int sum, int cnt) {
  if (dp[sum][cnt] != -1) {
    return dp[sum][cnt];
  }
  if (cnt == 4) {
    if (sum == n) {
      return 1;
    } else
      return 0;
  }
  long long int t = 0;
  for (int i = 0; i < 1000; i++) {
    if (i > n) {
      continue;
    }
    t += solve(sum + i, cnt + 1);
  }
  return dp[sum][cnt] = t;
}
