import java.util.Scanner;
public class Yuki80{
	public static void main(String[] arg){
		Scanner sc = new Scanner(System.in);
		int d,res;
		d = sc.nextInt();
		if(d % 4 == 0 || d % 4 == 1){
			res = (d/4)*(d/4);
		}else{
			res = (d/4)*(d/4+1);
		}
		System.out.println(res);
	}
}