class Member:
    def __init__(self, name):
        self.name = name
        self.limit = 3     
        self.borrowed = 0  

    def borrow_book(self):
        if self.borrowed >= self.limit:
            print("대출 불가")
        else:
            self.borrowed += 1
            print(f"대출 성공 ({self.borrowed}/{self.limit})")

class VIPMember(Member):
    def __init__(self, name):
        super().__init__(name)
        self.limit = 10

    def extend_period(self):
        print("대출 기간 연장 완료")

member = Member("홍길동")

member.borrow_book()
member.borrow_book()
member.borrow_book()
member.borrow_book()