class Screen(object):
    def __init__(self):
        self.__height = self.__width  =0    @property    def width(self):
        return self.__width

    @width.setter    def width(self,val):
        self.__width=val
    @property    def height(self):
        return self.__height
    @height.setter    def height(self,val):
        self.__height=val

    @property    def resolution(self):
        return self.__width*self.__height