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 may I help you? 
 customer: I want to book a flight ticket from LAX to DTW, can you please help me? 
 agent: Sure, please share your itinerary dates. 
 customer: My trip dates are 02/28 and 03/01. 
 agent: Please hold on for a while. 
 customer: Ok, please make sure that the connection limit is 1. 
 agent: May I know your name? 
 customer: Yes, my name is Deborah Young. 
 agent: Sorry Young, no flight is available on your route. 
 customer: It's ok, thank you for searching. 
 agent: Thank you for contacting us.
Output:
no_flight