class Point(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def distanceTo(self, other):
        return abs(self.x - other.x) + abs(self.y - other.y)

class Line(Point):
    def __init__(self, x, y, endpoint):
        super(Line, self).__init__(x, y)
        self.endpoint = endpoint
    def length(self):
        return self.distanceTo(self.endpoint)