You will be given a definition of a task first, then some input of the task.
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 Eric Taylor. 
 agent: Hello. How can I assist you today? 
 customer: Please make a plane reservation from DEN to PHL. 
 agent: Sure. Do you have any price limit? 
 customer: I can pay up to 1000. 
 agent: Let me know your travelling dates. 
 customer: I would start on 11/01 and return on 11/03 as I have a conference in between these dates. 
 agent: Please, wait. 
 customer: Ok. 
 agent: Thanks for waiting, there is no flights found on your route. 
 customer: That's Ok, thanks for the information. 
 agent: Thank you for availing us.
Output:
no_flight