Given the task definition and input, reply with output. 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

customer: Hi. 
 agent: Hello. 
 customer: I am Paul Hernandez. 
 agent: How can I help you? 
 customer: I am planning to travel from IAD to CLT, help me in booking a flight for me? 
 agent: Sure, I am glad to help you in booking process. Could you please share your journey dates? 
 customer: My travelling dates are 11/06 to 11/08. 
 agent: Thank you for waiting, there is a flight with 2 connection in UA airlines and price limit is 100. Shall I proceed? 
 customer: Proceed for booking. 
 agent: Ok, your ticket is booked with the flight 1017. 
 customer: Thank you. 
 agent: Thank you for choosing us.
book