Definition: 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
Input: customer: Hello, I am Sarah Rodriguez. 
 agent: Hello, how may I aid you today? 
 customer: I want to attend my nephew's birthday at Denver. Can you please help me in booking a flight ticket under the price of 1000? 
 agent: May I know your connection limit? 
 customer: I need a single connecting flight please make sure. 
 agent: Please provide me your travelling dates? 
 customer: My travelling dates are from 06/06 to 06/08. 
 agent: From which airport you want to start and which airport you want to land, can you please share your respective airport codes? 
 customer: I want to fly from TX - DFW  to CO - DEN. 
 agent: One moment, let me check the status and get back to you. 
 customer: Sure. 
 agent: Basis on your given dates, there is no flight found. 
 customer: It's alright, not a problem. 
 agent: Thank you for communicating with us. 
 customer: Thank you for your information.
Output:
no_flight