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: Hi. 
 agent: Hello. How can I assist you at this moment? 
 customer: I am Betty Robinson. I am planning to travel from DTW to LAS, can you help in booking? 
 agent: Sure Betty, I am happy to help you with that. Can I have your travel dates please? 
 customer: My travelling dates are 07/06 to 07/08. 
 agent: Ok, please wait a moment. 
 customer: Ok. 
 agent: Sorry Betty Robinson, no flight is available to you on your dates due to some weather conditions. 
 customer: That's ok, thank you for your help. 
 agent: Thank you for choosing us, have a good day.
Output:
no_flight