using System;

internal class Probram80
{
    public static void Main(string[] args)
    {
        int d = int.Parse(Console.ReadLine());
        if (d%2 == 1)
        {
            Console.WriteLine(0);
            return;
        }
        var half = d/2;
        var width = half / 2;
        var height = half - width;
        Console.WriteLine(width*height);
    }
}