Instructions: In this task, you are given a conversation between a flight agent and the customer. You are given 4 options and you need to select the goal of the conversation. It is provided as part of customer's context, which has to be one of the following: `book`: Make a new reservation, `cancel`: Cancel an existing reservation, `no_flight`: No flight found for the customer's preference, `no_reservation`: No reservation / No change / No cancellation was made in the conversation, mostly enquiring details
Input: customer: Hello. I am Elizabeth Young. 
 agent: Hello, how can I support you today? 
 customer: I want to celebrate my brother's birthday party at Belle Isle Park, which is at Detroit. For this I want to book a ticket from Washington with the price limit of 200. 
 agent: Sure. May I know your travelling dates? 
 customer: My travelling dates are from 01/04 to 01/06. 
 agent: To proceed booking I need your airport codes. 
 customer: Sure. I have to travel from IAD to DTW. With 1 connection. 
 agent: Ok. Please wait for a while. 
 customer: Ok. 
 agent: Thanks for being patience, there is a flight found with airline: AA and flight number:1020, price 100, 1 connection. Shall I proceed? 
 customer: Please, you proceed. 
 agent: Your ticket has been confirmed. 
 customer: Thank you for your service. 
 agent: Thank you for choosing us.
Output:
book