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 Ashley Lewis. 
 agent: How can I help you today? 
 customer: I have to attend a cultural festival in Oakland so please help me with flight ticket booking from New York city. 
 agent: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates? 
 customer: Thank you. I have to travel on dates of 29 Nov and return will be on Dec 01. 
 agent: Ok, may I know your travelling airport codes? 
 customer: Sure, I would like to travel from EWR to OAK. 
 agent: Please allow me a moment. 
 customer: Sure, take your time. 
 agent: Sorry, no flights are available on your route. 
 customer: Oh! It is sad to hear. Anyway, thank you for your time. 
 agent: Welcome, have a nice day.
no_flight