Instructions: 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
Input: customer: Hello. 
 agent: Hello. How can I assist you? 
 customer: I want a direct flight from PHX to LAX. Can you make a reservation for me? 
 agent: Sure, I can help you with that. May I know your preferable journey dates please? 
 customer: Sure, I want to airborne on 03/26 and recur on 03/28. 
 agent: Fine, please be on hold. 
 customer: Ok. 
 agent: May I know your good name please? 
 customer: Yes, I am Gary Lee. 
 agent: Sorry to inform you that there are no flights available for you on those dates. 
 customer: Ok, not a problem. Anyway's thank you for your information. 
 agent: Thank you for reaching us.
Output:
no_flight