Library System Management

You are required to implement a simple library management system. The library system manages a collection of books and registered members. Each book has a title, an author, and an availability status. Each member is identified by a unique member ID and can borrow books. However, a member may not borrow the same book more than once concurrently and can borrow at most three books at a time.

The system should support the following commands (read from stdin):

• ADD_BOOK <title> <author>: Add a book with the given title and author. The book is initially available.
• ADD_MEMBER <memberId>: Register a new member with the given member ID.
• BORROW <memberId> <bookTitle>: The member tries to borrow the book with the given title. The following messages should be printed to stdout:
  • If the book is successfully borrowed: Book borrowed successfully.
  • If the member already borrowed the same book: Cannot borrow the same book multiple times.
  • If the member already has three books: Cannot borrow more than three books.
  • If the book is not available or the member/book does not exist: Book is not available.
• RETURN <memberId> <bookTitle>: The member returns the book. Print:
  • If the book is returned successfully: Book returned successfully.
  • If the member did not borrow the book: Cannot return the book.

The input will start with a line containing an integer N representing the number of commands. Each of the following N lines will contain one command. Only the commands BORROW and RETURN produce an output line.

Note: All outputs should be printed on a separate line to stdout.

inputFormat

The first line of input contains an integer N, the number of commands. The following N lines each contain a command in one of the following formats:

• ADD_BOOK <title> <author>
• ADD_MEMBER <memberId>
• BORROW <memberId> <bookTitle>
• RETURN <memberId> <bookTitle>

Titles, authors, and member IDs will not contain spaces.

outputFormat

For each BORROW and RETURN command, output a single line containing the appropriate message as described in the problem statement.

## sample

5
ADD_BOOK 1984 GeorgeOrwell
ADD_MEMBER 001
BORROW 001 1984
RETURN 001 1984
BORROW 001 1984

Book borrowed successfully.
Book returned successfully.
Book borrowed successfully.

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