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
Q: customer: Hello. 
 agent: Hello, how may I aid you today? 
 customer: Can you please check for the flights on the route from BOS to DEN? 
 agent: Sure, can you please provide your departure and arrival dates? 
 customer: My journey dates are from Oct 20 to Oct 22. 
 agent: Are you looking for any preferred class? 
 customer: Any class will be ok but my depart time will be in afternoon. 
 agent: Do you have any other specifications to be met? 
 customer: I need 1 connection flight. 
 agent: Kindly mention your name? 
 customer: Myself Mark Phillips. 
 agent: We have found a connected flight of United airlines, flight number-1018 class-economy depart time-afternoon 15:00 PM and fare is 200. 
 customer: Please book it. 
 agent: Sure, your ticket has been booked. 
 customer: Thank you for helping me.
A:
book