class Point(object):
    """Represents a point in 2-D space."""

class Rectangle(object):
    """Represents a rectangle

    attributes: width, height, corner.
    """

def create_rectangle(x, y, width, height):
    pt = Point()
    pt.x = x
    pt.y = y
    r = Rectangle()
    r.width = width
    r.height = height
    r.corner = pt
    return r

def area_difference(r1, r2):
    area1 = r1.width * r1.height
    area2 = r2.width * r2.height
    return area1 - area2

r1 = create_rectangle(10, 20, 10, 10)
r2 = create_rectangle(20, 50, 15, 20)
print(area_difference(r1, r2))