import java.util.*;
public class FizzBuzzString{
	
	static int fi = 4;
	static int tf = 2;

	public static void main(String... args){
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		long res = 0;
		for(long i = 1; i <= n; i++){
			if(i%3 == 0){
				res+=tf;
			}
			if(i%5==0){
					res+=tf;
			}
		}
		System.out.println(res);
	}

}