class Yukicoder
  def initialize
    d = gets.to_i

    if d % 4 == 0
      puts (d/4) ** 2
    elsif d % 4 == 3
      puts (d/4) * ((d/4)+1)
    elsif d % 4 == 2
      puts (d/4) * ((d/4)+1)
    else
      puts (d/4) ** 2
    end
  end
end

Yukicoder.new