#include <bits/stdc++.h>
using namespace std;
int dp[5][4444];
int solve(int k, int sum) {
  if (k == 4) return sum ? 0 : 1;
  if (dp[k][sum]) return dp[k][sum];
  int ret = 0;
  for (int i = 0; i <= 1000 && i <= sum; i++) {
    ret += solve(k + 1, sum - i);
  }
  return dp[k][sum] = ret;
}
int main(void) {
  int n;
  while (cin >> n) {
    cout << solve(0, n) << endl;
  }
}
