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, I am Matthew Evans. 
 agent: Hello, how may I assist you? 
 customer: I am having an interview at Chicago. Can you book a ticket for me? 
 agent: Sure, I am here to help you. May I know your travel dates please? 
 customer: I am planning to start on 08/07 and return back on 08/09. 
 agent: Ok, may I know your airport codes please? 
 customer: Search for the flight available from PHX to ORD. 
 agent: Ok, hold on for a moment. Let me check the best flight for you. 
 customer: Take your time but make sure that connection limit is 1. 
 agent: Sorry Evans, there are no flights available on your requested dates. 
 customer: No issues. Thank you for checking. 
 agent: Welcome, thank you for choosing us. Have a great day.
Output:
no_flight