package m.shin;
import java.util.Scanner;
public class Con311 {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		long n = s.nextLong();
		s.close();

		long count = 0;
		count = n / 3 * 2 + n / 5 * 2;
		System.out.println(count);

	}

}