import java.util.Scanner;

public class Main80 {
	public static void main(String[] args) {
		Main80 p = new Main80();
	}

	public Main80() {
		Scanner sc = new Scanner(System.in);
		int d = sc.nextInt();
		solve(d);
	}

	public void solve(int d) {
		int res = (d/4) * ((d-d/4*2)/2);
		System.out.println(res);
	}

}