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 may I help you? 
 customer: I am Susan Smith, want to travel from AUS to DFW for business trip. Please help me in ticket booking. 
 agent: Sure, may I know your trip dates please? 
 customer: My trip dates are from 10/21 to 10/22. 
 agent: Please wait for a while. 
 customer: Ok. Please check for direct flight. 
 agent: Sorry, there is no direct flight available which is travelling to your destination. 
 customer: That's fine, thank you. 
 agent: Most welcome.
A:
no_flight