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 at this moment? 
 customer: I would like to book a ticket from DTW to LGA, can you please help me out? 
 agent: Sure, I am here to help you with that. Can I know your planned trip dates? 
 customer: I am travelling on these dates April 2nd and 4th. 
 agent: Ok, do you have any other requirements? 
 customer: I need single connected flight. 
 agent: May I know your name? 
 customer: Jeffery Collins here. 
 agent: Is there any other requirements? 
 customer: I don't have any other preferences. 
 agent: Please wait for a minute. 
 customer: Sure. 
 agent: Sorry to say that, there are no flights available based on your travelling dates. 
 customer: Ok no problem, thank you for your services. 
 agent: Thank you for reaching us.
Output:
no_flight