class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            if(n < 4)
            {
                Console.WriteLine("0");
            }
            else
            {
                int area = 0;
                if(n%4 < 2)
                {
                    int side = n/4;
                    area = side * side;
                }
                else
                {
                    int vertical = n /4;
                    int horizontal = n / 4 + 1 ;
                    area = vertical * horizontal;
                }
                Console.WriteLine(area);
            }

        }
    }