import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int l = sc.nextInt();
if(1 <= l % 5 && l % 5 <= 4) {
System.out.println(l / 5 + 1);
}else {
System.out.println(l / 5);
}
sc.close();
}
}