class Screen(object):

 @property

 def width(self):

  return self._width

 @width.setter

 def width(self,value):

  self._width = value

 @property

 def height(self):

  return self._height

 @height.setter

 def height(self,value):

  self._height = value

 @property

 def resolution(self):

  return self._width * self._height