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: Hi. 
 agent: Hello. 
 customer: I am Dennis Lopez here. 
 agent: How can I help you? 
 customer: I want to reserve my ticket from PHX to AUS, can you please help me out? 
 agent: Can I know your travel dates? 
 customer: Sure, my planned dates of journey are from Oct, 21 to Oct, 23. 
 agent: Do you have any preferences? 
 customer: Yes, I need a depart and return timing at morning. 
 agent: Do you have any connection limit? 
 customer: Yes, I need a connecting flight. 
 agent: Sorry, I did not find any flights for you. 
 customer: Ok, no problem. Thank you for your service. 
 agent: Thank you for reaching us.
Output:
no_flight