import java.util.Scanner;

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 = 0; i < n; i++) {
			if(i%3!=0 && i%5!=0) {
				sum += i;
			}
		}
		System.out.println(sum);
		
	}
	
}
