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. 
 agent: Hello. 
 customer: I am James Robinson. 
 agent: How can I assist you? 
 customer: I am planning to attend a meeting. Can you please book a ticket from DCA to DCA? 
 agent: Sure, help me with the travelling dates? 
 customer: My travelling dates are 06/14 and return on 06/16. 
 agent: Give me a minute. 
 customer: Sure. 
 agent: There is a flight with number 1020 in airline Frontier. 
 customer: Yes, you can book it. 
 agent: Your ticket is confirmed, happy journey. 
 customer: Thank you for your help. 
 agent: Thank you for opting us.
book