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 be your help? 
 customer: This is Katherine Baker, can you help me to book a flight ticket from MSP to PHX? 
 agent: Sure, please share your planned travel dates. 
 customer: I am travelling from Feb 15 to Feb 17. 
 agent: Do you prefer either economy or business class? 
 customer: I prefer business class. 
 agent: Please let me know if you have any other preference. 
 customer: Yes, I need a halt in between my journey. 
 agent: Sure, please wait for a while. 
 customer: Sure. 
 agent: Sorry to inform you that there is no flight available on given dates from you. 
 customer: That's ok, no problem. Thank you for the information. 
 agent: Thank you. We hope to serve you better next time.
Output:
no_flight