import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    long ans = 0;
    for (int i = 1; i <= N; i++) {
      if (i % 3 == 0 || i % 5 == 0) continue;
      ans += i;
    }
    System.out.println(ans);
  }
}
