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: Hi. 
 agent: Hello. How can I help you now? 
 customer: I am Carol Baker. 
 agent: Ok. 
 customer: Can you help me to book a flight from IAD to ATL? 
 agent: Sure, can you please mention the travelling dates of your journey? 
 customer: My trip dates are 04/15 and 04/17. 
 agent: Ok, please wait for a while. 
 customer: Sure. 
 agent: Sorry Carol, there are no flights found on your requested dates. 
 customer: Oh! ok. 
 agent: Thank you for approaching us, have a nice day. 
 customer: Thank you for your time. 
 agent: You are welcome.
Output:
no_flight