class Element:
    def __str__(self):
        return self.__class__.__name__

    def __add__(self, other):
        key = type(self), type(other)
        if key in TRANSFORMATIONS_TABLE:
            return TRANSFORMATIONS_TABLE[key]()

        key = type(other), type(self)
        if key in TRANSFORMATIONS_TABLE:
            return TRANSFORMATIONS_TABLE[key]()


class Water(Element):
    pass


class Air(Element):
    pass


class Fire(Element):
    pass


class Dirt(Element):
    pass


class Storm(Element):
    pass


class Vapor(Element):
    pass


class Mud(Element):
    pass


class Lightning(Element):
    pass


class Dust(Element):
    pass


class Lava(Element):
    pass


TRANSFORMATIONS_TABLE = {
    (Water, Air): Storm,
    (Water, Fire): Vapor,
    (Water, Dirt): Mud,
    (Air, Fire): Lightning,
    (Air, Dirt): Dust,
    (Fire, Dirt): Lava,
}


def main():
    print(f"{Water()} + {Air()} = {Water() + Air()}")
    print(f"{Water()} + {Fire()} = {Water() + Fire()}")
    print(f"{Water()} + {Dirt()} = {Water() + Dirt()}")
    print(f"{Air()} + {Fire()} = {Air() + Fire()}")
    print(f"{Air()} + {Dirt()} = {Air() + Fire()}")
    print(f"{Fire()} + {Dirt()} = {Fire() + Dirt()}")


if __name__ == "__main__":
    main()