import java.io.*;

public class FizzBuzz {

	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		
		long n = Long.parseLong(br.readLine());
		
		long fizz,buzz;
		fizz=n/3;
		buzz=n/5;
		
		System.out.println(2*(fizz+buzz));
	}

}