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. 
 customer: I'm Barbara Collins. 
 agent: How can I help you? 
 customer: I want to attend a music event in Las Vegas. 
 agent: Ok. 
 customer: Can you book a ticket from CLT to LAS? I want to have 1 connecting flight. 
 agent: Please tell your travelling dates? 
 customer: I want to depart on 01/08 and return on 01/10. 
 agent: With your request the flight is available with 2 connection of flight. Are you ok with it? 
 customer: No, I would like to have 1 connection only. 
 agent: Sorry, there are no flights with your request. 
 customer: That's ok. Thank you for your help. 
 agent: Thank you and have a nice day.
Output:
no_flight