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. 
 agent: Hello, how may I aid you today? 
 customer: I am Michelle Johnson. I need to book a flight ticket from CO-DEN to TX-DFW, Can you please help me that? 
 agent: Could you please share your planned dates? 
 customer: I would like to travel on 05/07 to arrival on 05/09. 
 agent: Do you have any other restrictions to be met? 
 customer: I need single connection limit under fare of 1000. 
 agent: Ok, please hold a moment. 
 customer: Sure. 
 agent: Thanks for your time, sorry, unfortunately no flights found on that route. 
 customer: Ok, no problem. Thanks for your information. 
 agent: Thank you for opting us, have a great day ahead.
Output:
no_flight