import java.util.*;
public class Main {

  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      long sum = 0;
      for(int i = 1; i<= n; i++) {
        if(i % 3 != 0 && i % 5 != 0)
          sum += i;
      }
      System.out.println(sum);
  }
}