import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        int d = koko.nextInt();
        int t = 0;
        int y = 0;
        if(d%4==0){
            t=d/4;
            y=d/4;
        }else if(d%4==2){
            t=(d+2)/4;
            y=(d-2)/4;
        }else{
            int n = (d-1)/2;
            if(n%2==0){
                t=n/2;
                y=n/2;
            }else{
                t=(n+1)/2;
                y=(n-1)/2;
            }
        }
        System.out.println(t*y);
        
    }
}