1. def purchase_flag(balance):
2.     while True:
3.         print("Welcome to the CTF Store Challenge!")
4.         print("Your balance: $" + str(balance))
5.         print("Options:")
6.         print("1. Curtains of Houses - $4")
7.         print("2. Dining Table - $30")
8.         print("3. Flag of the Office - $49")
9.         print("4. Another item (Search for items)")
10.         print("5. Exit")
11.  
12.         choice = input("Enter your choice: ")
13.  
14.         if choice == "1":
15.             if balance >= 4:
16.                 balance -= 4
17.                 print("You purchased the Curtains of Houses. Your balance is now $" + str(balance))
18.             else:
19.                 print("You don't have enough money to buy the Curtains of Houses.")
20.  
21.         elif choice == "2":
22.             if balance >= 30:
23.                 balance -= 30
24.                 print("You purchased the Dining Table. Your balance is now $" + str(balance))
25.             else:
26.                 print("You don't have enough money to buy the Dining Table.")
27.  
28.         elif choice == "3":
29.             if balance >= 49:
30.                 balance -= 49
31.                 print("Congratulations! You purchased the Flag of the Office, which is the challenge flag.")
32.                 print("Your balance is now $" + str(balance))
33.                 return True
34.             else:
35.                 print("You don't have enough money to buy the Flag of the Office.")
36.  
37.         elif choice == "4":
38.             while True:
39.                 print("Searching for item...")
40.                 item = input("Enter the item you want to search for: ")
41.                 try:
42.                     result = eval(item)
43.                     balance = result
44.                     print("Sorry, the item you are looking for is not available.")
45.                 except Exception:
46.                     print("Invalid input. Please enter a valid expression.")
47.                 print("Options:")
48.                 print("1. Search again")
49.                 print("2. Back to list")
50.  
51.                 search_choice = input("Enter your choice: ")
52.                 if search_choice == "1":
53.                     continue
54.                 elif search_choice == "2":
55.                     break
56.                 else:
57.                     print("Invalid choice. Returning to the list of options.")
58.  
59.         elif choice == "5":
60.             print("Exiting the CTF Store Challenge. Goodbye!")
61.             return False
62.  
63.         else:
64.             print("Invalid choice. Please enter a number between 1 and 5.")
65.  
66. balance = 10
67. purchase_flag(balance)
68.