# 请利用@property给一个Screen对象加上width和height属性，以及一个只读属性resolution：
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 '{} x {}'.format(self._width, self._height)


# ------------
s = Screen()
s.width = 1920
s.height = 1080
print('resolution: %d x %d\n' % (s.width, s.height))