Q: 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. How can I help you? 
 customer: Can you please help me to book a flight ticket from DTW to AUS? 
 agent: Can you give me your travel dates? 
 customer: My travelling dates are Mar 21 and Mar 23. 
 agent: Do you need any connections? 
 customer: I need a connecting flight. 
 agent: Do you have any other preferences? 
 customer: My class preference is business. 
 agent: May I know your name? 
 customer: My name is Kenneth Green. 
 agent: sorry to say that, there are no flights available with your details. 
 customer: No problem, thank you for your information. 
 agent: Thank you for reaching us.
A:
no_flight