class Coin:
  def __init__(self):
    self.size = None

  def set_size(self, size):
    self.size = size

  def describe(self):
    return "Unknown coin"

class Coin:
  def __init__(self):
    self.size = None

  def set_size(self, size):
    self.size = size

  def describe(self):
    return "Unknown coin"
