import java.util.Scanner;

public class Main {

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int half=n/2;
		int a=half/2;
		int b=(int) Math.ceil(half/2.0);
		System.out.println(a*b);
	}
}