You will be given a definition of a task first, then some input of the task.
In this task, you're given a dialogue between a customer and a flight booking agent with a gap in the conversation. Your job is to find the answer of the previous dialogue. Avoid using irrelevant extra information while creating the answer. The answer should be relevant to the question before the blank. If you fill the blank with a question, it should have an answer from the agent in the given dialogue. Fill the gap marked with underline.

customer: Hello, I am Ryan King. 
 agent: Hello, how can I assist you today? 
 __ 
 agent: Ok King, may I know your travel dates please? 
 customer: Sure, I would like to go on 01/29 and return back on 01/31. 
 agent: Ok, please be on hold. 
 customer: Ok, ensure it is a single connecting flight. 
 agent: thank you for the waiting, here there is a flight available as per your request and air fare is about 100. Shall I book it? 
 customer: Ok, please proceed for further. 
 agent: Your booking is done with flight number 1018. 
 customer: Thank you for booking. 
 agent: You are welcome. Thank you for reaching us, have a nice day. 
 customer: Welcome.
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
customer: Can you please book a ticket from DFW to AUS?