Definition: 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 assist you? 
 customer: I am Charles Williams. I need a direct flight to visit a The Mirage Restaurant in Las Vegas, can you assist me for booking a flight ticket? 
 agent: Sure, I will assist you in ticket booking. Please provide your travel dates and price limit? 
 customer: My travelling dates are from 07/04 to 07/06. My price limit should not exceed with 200. 
 agent: Ok, let me know your source and destination point? 
 customer: It is an round trip, my source and destination is Las Vegas, NV - LAS. 
 agent: Ok. Sorry to inform you that there was no flights found on your dates. 
 customer: Ok, no issue. Thanks for your quick response. 
 agent: Thank you for opting us, have a good day.
Output:
no_flight