import java.util.Date;
import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		long exec_time=new Date().getTime();
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long ans=2*((long)n/3+(long)n/5);
		System.out.println(ans);
		System.err.println(new Date().getTime()-exec_time+"ans");
	}
}