class Integer < Data4
  def <(right)
    X.comparison(:<)
  end
  def -(right)
    X.int_operator(:-)
  end
end
class Space

  def down( n )
    if( n <  2 )
      return n
    else
      a = down(n - 1)
      return a
    end
  end

  def main(arg)
    return down(10)
  end

end