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: Hello, I am Janet Harris. 
 agent: Hello, how can I assist you? 
 customer: I am planning to celebrate Christmas Day with my family in Minneapolis, can you please help me to book a flight ticket? Make sure that my price limit is 5000. 
 agent: Sure, may I  know your journey dates to check the availability of flights. 
 customer: And I need a flight with single connection. My journey dates are from 12/24 to 12/26. 
 agent: Please provide your airport codes. 
 customer: I am travelling from DTW to MSP. 
 agent: We found a flight with Hawaiian airlines and price is 100 with single connection of 1021 flight. Shall I proceed for booking? 
 customer: Ok, you can proceed with my booking. 
 agent: Your ticket has been confirmed. 
 customer: Thanks for your service. 
 agent: Thanks for choosing us. 
 customer: Thank you.
book