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: Hi, Michelle Carter here. 
 agent: Hello Carter, how can I assist you? 
 customer: I have planned to celebrate my wedding anniversary in Las Vegas, can you please help me to book my ticket from IAH to LAS? 
 agent: Sure Carter, when are you planning your journey? 
 customer: My wedding anniversary is on 12/11, so I want to depart on 12/10 and return on 12/12. 
 agent: Please wait a minute while I check for best flights available for you. 
 customer: Sure, take your time. 
 agent: Carter, I have found a flight available with price 100 inclusive of all taxes. Shall I book the ticket? 
 customer: That's great, please proceed with booking my ticket. 
 agent: Your ticket is confirmed with Hawaiian airlines and flight number is 1019. 
 customer: Thank you very much for booking my ticket. 
 agent: Thank you for utilising our services. Hope you like our service.
Output:
book