import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

class Book {
    private String title;
    private String author;
    private boolean isAvailable;

    public Book(String title, String author) {
        this.title = title;
        this.author = author;
        this.isAvailable = true;
    }

    public String getTitle() {
        return title;
    }

    public String getAuthor() {
        return author;
    }

    public boolean isAvailable() {
        return isAvailable;
    }

    public void borrowBook() {
        if (isAvailable) {
            isAvailable = false;
            System.out.println("Book '" + title + "' has been borrowed.");
        } else {
            System.out.println("Book '" + title + "' is not available.");
        }
    }

    public void returnBook() {
        if (!isAvailable) {
            isAvailable = true;
            System.out.println("Book '" + title + "' has been returned.");
        } else {
            System.out.println("Book '" + title + "' was not borrowed.");
        }
    }

    @Override
    public String toString() {
        return "Title: " + title + ", Author: " + author + ", Available: " + isAvailable;
    }
}

class User {
    private String name;
    private List<Book> borrowedBooks;

    public User(String name) {
        this.name = name;
        this.borrowedBooks = new ArrayList<>();
    }

    public String getName() {
        return name;
    }

    public void borrowBook(Book book) {
        if (book.isAvailable()) {
            borrowedBooks.add(book);
            book.borrowBook();
        } else {
            System.out.println("Book '" + book.getTitle() + "' is not available.");
        }
    }

    public void returnBook(Book book) {
        if (borrowedBooks.contains(book)) {
            borrowedBooks.remove(book);
            book.returnBook();
        } else {
            System.out.println("You did not borrow the book '" + book.getTitle() + "'.");
        }
    }

    public List<Book> getBorrowedBooks() {
        return borrowedBooks;
    }

    @Override
    public String toString() {
        return "User: " + name + ", Borrowed Books: " + borrowedBooks.size();
    }
}

class Library {
    private List<Book> books;
    private List<User> users;

    public Library() {
        this.books = new ArrayList<>();
        this.users = new ArrayList<>();
    }

    public void addBook(Book book) {
        books.add(book);
    }

    public void addUser(User user) {
        users.add(user);
    }

    public Book findBookByTitle(String title) {
        for (Book book : books) {
            if (book.getTitle().equalsIgnoreCase(title)) {
                return book;
            }
        }
        return null;
    }

    public User findUserByName(String name) {
        for (User user : users) {
            if (user.getName().equalsIgnoreCase(name)) {
                return user;
            }
        }
        return null;
    }

    public void displayBooks() {
        for (Book book : books) {
            System.out.println(book);
        }
    }

    public void displayUsers() {
        for (User user : users) {
            System.out.println(user);
        }
    }
}

public class LibraryManagementSystem {
    public static void main(String[] args) {
        Library library = new Library();
        Scanner scanner = new Scanner(System.in);

        while (true) {
            System.out.println("\nLibrary Management System");
            System.out.println("1. Add Book");
            System.out.println("2. Add User");
            System.out.println("3. Borrow Book");
            System.out.println("4. Return Book");
            System.out.println("5. Display Books");
            System.out.println("6. Display Users");
            System.out.println("7. Exit");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume newline

            switch (choice) {
                case 1:
                    System.out.print("Enter book title: ");
                    String title = scanner.nextLine();
                    System.out.print("Enter book author: ");
                    String author = scanner.nextLine();
                    Book book = new Book(title, author);
                    library.addBook(book);
                    System.out.println("Book added successfully.");
                    break;
                case 2:
                    System.out.print("Enter user name: ");
                    String name = scanner.nextLine();
                    User user = new User(name);
                    library.addUser(user);
                    System.out.println("User added successfully.");
                    break;
                case 3:
                    System.out.print("Enter user name: ");
                    String userName = scanner.nextLine();
                    User borrower = library.findUserByName(userName);
                    if (borrower != null) {
                        System.out.print("Enter book title: ");
                        String bookTitle = scanner.nextLine();
                        Book borrowedBook = library.findBookByTitle(bookTitle);
                        if (borrowedBook != null) {
                            borrower.borrowBook(borrowedBook);
                        } else {
                            System.out.println("Book not found.");
                        }
                    } else {
                        System.out.println("User not found.");
                    }
                    break;
                case 4:
                    System.out.print("Enter user name: ");
                    String returnerName = scanner.nextLine();
                    User returner = library.findUserByName(returnerName);
                    if (returner != null) {
                        System.out.print("Enter book title: ");
                        String returnBookTitle = scanner.nextLine();
                        Book returnedBook = library.findBookByTitle(returnBookTitle);
                        if (returnedBook != null) {
                            returner.returnBook(returnedBook);
                        } else {
                            System.out.println("Book not found.");
                        }
                    } else {
                        System.out.println("User not found.");
                    }
                    break;
                case 5:
                    library.displayBooks();
                    break;
                case 6:
                    library.displayUsers();
                    break;
                case 7:
                    System.out.println("Exiting...");
                    scanner.close();
                    System.exit(0);
                default:
                    System.out.println("Invalid option. Please try again.");
            }
        }
    }
}