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 can I help you? 
 customer: I would like to visit the Tiny Gardens at Denver. Can you please help me in booking a ticket? 
 agent: Sure, may I know your name please? 
 customer: My name is Anthony Collins. 
 agent: Anthony, can you please help me with your journey details? 
 customer: Well, I am planning to travel on dates 11/12 and 11/14 from AUS to DEN. 
 agent: Just hold on for few seconds, I will get you back with the flight details. 
 customer: Sure. 
 agent: Sorry Anthony, there is no flight available on those dates. 
 customer: That's fine, not a big deal. Thank you for the information. 
 agent: Thank you for approaching us.
Output:
no_flight