You will be given a definition of a task first, then some input of the task.
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

customer: Hello. 
 agent: Hello. How can I serve you? 
 customer: I am Paul Thompson want to visit Charlotte, can you book a ticket on 08/08 and 08/10? 
 agent: Sure, I can help you. Can I know your preferable airport codes? 
 customer: Sure, I want to travel from DEN to CLT. 
 agent: Do you have any connection limit? 
 customer: Yes, I need a flight with 1 connection. 
 agent: Please wait a while. 
 customer: Ok. 
 agent: Thanks for your time. We found a Hawaiian airline, flight number:1013 and the price is 100. 
 customer: Ok, proceed with my booking. 
 agent: Your flight ticket has been confirmed. 
 customer: Thank you. 
 agent: Thank you for choosing us.
Output:
book