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. I am Nancy Hall. 
 agent: Hello, how may I assist you at this moment? 
 customer: I want to travel from DFW to IAH. Can you help me to book a flight ticket? 
 agent: Sure, I am here to help you in booking. Kindly provide your travel dates to reserve a flight. 
 customer: I want to fly in the flight on 04/01 and 04/03. 
 agent: Ok, please be on hold, let me check for the flight availability. 
 customer: Ok, take your own time. 
 agent: Hawaiian airlines is having a flight with a single halt and ticket fare is 100, shall I proceed with booking? 
 customer: Proceed to booking. 
 agent: Ok, your ticket has been reserved with the flight-1006. 
 customer: Thank you for your help. 
 agent: Welcome, have a happy journey.
Output:
book