using System;

public class No311 {
	public static void Main() {
	    long f = long.Parse(Console.ReadLine());
	    long count = 0;
	    for(var i = 1; i < f+1; i++ ){
	       count = ( i % 3 == 0 ) ? count+=2 : count;
	       count = ( i % 5 == 0 ) ? count+=2 : count;
	    }
        Console.WriteLine(count);
	}
}