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

Example input: customer: Hi. 
 agent: Hello. How can I help you? 
 customer: I would like to change my existing reservation as my plan to go for a holiday trip got postponed. Can you please help me with this? 
 agent: Sure, may I know your name please? 
 customer: My name is Anthony Phillips. 
 agent: Please wait a moment. 
 customer: Sure. 
 agent: Unfortunately there is no reservation found with your given name. 
 customer: Not a problem, thank you for checking. 
 agent: Thank you for choosing us.
Example output: no_reservation
Example explanation: Here the customer has not asked for any booking, he just wanted to update his already booked flight, so the status would be no_reservation
Q: customer: Hello. 
 agent: Hello, how may I help you? 
 customer: Myself Mark Brown here. I  need to fly Las Vegas for my college admission, could you please help me in booking my flight ticket from ATL to LAS? 
 agent: Sure, can you please let me know your journey dates that you wish to travel? 
 customer: My travel dates are 11/11 and 11/13. 
 agent: Do you need a flag stop in between your journey? 
 customer: I need a connecting flight. 
 agent: May I know how much do you want to spend on flight ticket? 
 customer:  I can spend upto 500. 
 agent: Please wait for a while. 
 customer: OK. 
 agent: We found a flight in Southwest airlines, flight number is 1005 with one connection price is 100. Shall I proceed? 
 customer: Ok, you can proceed. 
 agent: Ok, your ticket has been confirmed in economy class. 
 customer:  Thank you for booking. 
 agent: Thank you for opting us.
A:
book