Detailed 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
Q: customer: Hello. 
 agent: Hello, how may I help you? 
 customer: I am Ronald Hernandez. I need to book a flight ticket to attend an interview at CLT, Can you please help me for booking from DEN? 
 agent: Sure, may I know your trip dates please? 
 customer: I would like to travel on 09/24 and return on 09/26. 
 agent: Please wait for a while. 
 customer: Sure. 
 agent: Sorry, there is no flight available as per your request. 
 customer: Ok, no problem. Thanks for your information. 
 agent: Most welcome.
A:
no_flight