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: Hi. 
 agent: Hello. 
 customer: I am Mary Martin. 
 agent: How can I help you? 
 customer: Can you please reserve me a flight ticket from Washington, DC - IAD to Austin, TX - AUS? 
 agent: Sure, I am glad to help you. Could you please share your travelling dates? 
 customer: My trip dates are 04/25 - 04/27. 
 agent: Thank you for waiting, there are no flights found on your preferable dates. 
 customer: Not a problem, thank you. 
 agent: Thank you for choosing us.
no_flight