class Fixnum
  def *(arg)
    self - (-arg)
  end

  def +(arg)
    tmp = self
    (arg-1).times{
      tmp -= -self
    }
    tmp
  end
end

class Yukicoder
  def initialize
    s = gets.chomp

    puts eval(s).to_i
  end
end

Yukicoder.new