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 Scott Collins. 
 agent: Hello, how can I aid you? 
 customer: I want to visit HOU, can you help me with single connection of flight? 
 agent: Sure, can you help me with your journey dates? 
 customer: My depart is on 12/22 and return on 12/24. 
 agent: May I know your origin point? 
 customer: My origin is PHL. 
 agent: Sorry, no flights found on your given details. 
 customer: No problem, thank you. 
 agent: Thank you for reaching us.
Output:
no_flight