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. How may I help you? 
 customer: I am Paul Scott,want to travel from OAK to IAD. 
 agent: So, I want to book you a flight ticket? 
 customer: Yes. 
 agent: Sure, I will can you provide me your travelling dates? 
 customer: Sure,my travelling dates will be from 01/18 to 01/20. 
 agent: Do you have any limitations on your price and connectionlimit? 
 customer: The flight should be with 1 connection and the price should be with in 200. 
 agent: Paul Scott unfortunately there is no flights which matches your requirements. Thank you for reaching us. 
 customer: It's OK.
no_flight