#include <bits/stdc++.h>
void sum_of_2_int(int n, int sum, int i, int *count, int *list) {
  if (n < sum) {
    return;
  }
  if (i < 2) {
    for (int j = 0; j <= 1000; ++j) {
      list[i] = j;
      sum_of_2_int(n, sum + j, i + 1, count, list);
    }
  } else {
    if (n == sum) {
      (*count)++;
    }
  }
}
int main() {
  int combs[2001] = {};
  for (int i = 0; i <= 2000; ++i) {
    int list[2] = {};
    int combination = 0;
    sum_of_2_int(i, 0, 0, &combination, list);
    combs[i] = combination;
  }
  int n;
  while (std::cin >> n) {
    int comb = 0;
    for (int i = 0; i <= 2000; ++i) {
      int list[2] = {};
      int x0 = i;
      int x1 = n - x0;
      if (x1 < 0) {
        continue;
      }
      int combination = 0;
      sum_of_2_int(x1, 0, 0, &combination, list);
      comb += combs[x0] * combination;
    }
    std::cout << n << std::endl;
  }
  return 0;
}
