class Base:
    def __init__(self):
        print("B ", end="")
    def __del__(self):
        print("~B ", end="")

class Derived(Base):
    def __init__(self):
        super().__init__()
        print("D ", end="")
    def __del__(self):
        print("~D ", end="")

def main():
    p = Derived()
    del p

main()