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, may I know your name please? 
 customer: Yes, myself Sandra Taylor. 
 agent: How can I help you? 
 customer: I want to book a flight ticket from DEN to DCA. 
 agent: May I know your travelling dates please? 
 customer: I want travel in the dates of 12/10 and 12/12. 
 agent: Sorry Sandra, there are no flights available regarding your journey. 
 customer: Ok, thank you for your information. 
 agent: Thank you and have a nice day.
no_flight