import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long D = scan.nextLong();
		scan.close();
		long x,y;
		if(D % 4 == 0 || D % 4 == 1) {
			x = D / 4;
			y = D / 4;
		}else {
			x = D / 4;
			y = D / 4 + 1;
		}
		System.out.println(x * y);
	}
}