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
Q: customer: Hello,. 
 agent: Hello, how can I aid you? 
 customer: Can you please help me in booking my flight ticket from DTW to AUS? 
 agent: I am here to help you with your concern. Sure, can you please let me know your travel dates? 
 customer: My planned travel dates are Aug 20-22. 
 agent: Would you like to fly with connecting flight or direct flight? 
 customer: I prefer to fly in connected flight. 
 agent: Are you looking for economy class flight or business class flight? 
 customer: I am comfortable with any class. 
 agent: Are you comfortable with any time for depart and arrival journey? 
 customer: No, but I would prefer not to fly a low-cost airline. 
 agent: May I know your airline preference for your journey? 
 customer: I would prefer not to fly a low-cost airline. 
 agent: Could you help me with your name please, so I can check with the flights availability? 
 customer: Myself, Anna Robinson. 
 agent: Thank you for sharing all the required information, Anna Robinson. Please allow me 2-3 minutes. 
 customer: Ok. 
 agent: Thank you for waiting. Sorry, there is no flight available for the mentioned dates. 
 customer: Ok, no issues. Thank you for your service. 
 agent: Thank you for reaching us!.
A:
no_flight