import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        long N = sc.nextLong();

        long zCount = 0;

        for (long i = 0; i < N; i++) {

            if (i % 3 == 0) {
                zCount += 2;
            }

            if (i % 5 == 0) {
                zCount += 2;
            }

        }

        System.out.println(zCount);

    }

}