using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;


class Magatro
{
    static int D = int.Parse(Console.ReadLine()) / 2;
    static void Main()
    {
        int ans = (D / 2) * ((D + 1) / 2);
        Console.WriteLine(ans);

   
    }
}