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 may I aid you? 
 customer: I am Eric Baker want to present my documentation in National Conference at NY-EWR. Can you book a ticket from TX-HOU? 
 agent: Sure, we are perky to serve you. May I know your trip dates? 
 customer: My trip dates are 02/10 and 02/12. 
 agent: Sorry to inform you that, no flights are available based on your requirements. 
 customer: Ok, no issues. Thank you for your help. 
 agent: Thank you for choosing us.
Output:
no_flight