Instructions: 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 may I oblige you today? 
 customer: Myself Scott Brown. I want to make my flight reservation to meet my brother at Dallas, can you please help me in booking my flight ticket? 
 agent: Sure, may I know your travelling dates? 
 customer: I want to depart on Jan 26th and I will return back on Jan 28th. 
 agent: Could you please share your take off airport code? 
 customer: Sure, I want to travel from DEN to DFW. 
 agent: Ok, please wait for a minute. 
 customer: Sure. 
 agent: Thank you for waiting, there are no flights found from your source. 
 customer: Sad to hear that. Anyway, thank you for the information. 
 agent: Thank you for availing us.
Output:
no_flight