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: Hello. 
 agent: Hello, how can I assist you? 
 customer: Can you help me booking a flight ticket from DTW to AUS? 
 agent: Sure, I can help you with that. May I know your travel dates please? 
 customer: I will start on 05/08 and return on 05/10. 
 agent: Do you need break in between your journey? 
 customer: I need a direct flight. 
 agent: Please let me know if you have any other specifications. 
 customer: No. 
 agent: May I know your good name please? 
 customer: I am Richard Lopez. 
 agent: Sorry to inform you that there are no direct flights available for you on those dates. 
 customer: No problem, thank you for the information. 
 agent: Thank you for reaching us.
Output:
no_flight