import java.util.Scanner;

public class No311 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		
		int fizz = n / 3;
		int buzz = n / 5;
		
		System.out.println(2 * (fizz + buzz));
		sc.close();
	}

}