Definition: 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. I am Jerry King. 
 agent: How can I help you? 
 customer: Can you book a flight ticket for me from IAH to EWR? 
 agent: May I know your trip dates? 
 customer: My trip dates are on 05/20 and back on 05/22. 
 agent: Sorry, there are no flights that are moving to your region when I have checked on those dates. 
 customer: Ok, no problem with that one, thank you for your search and information. 
 agent: Thank you for reaching us, have a nice day.
Output:
no_flight