

import java.util.Scanner;

public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long n = sc.nextLong();

		long ans = 0;

		for (int i = 1; i <= n; i++) {
			if (i % 3 != 0 && i % 5 != 0)
				ans += i;
		}

		System.out.println(ans);
	}

}
