Instructions: 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. What can I do for you? 
 customer: Dorothy Roberts here. I would like to visit space centre which in Houston, can you book the ticket for me? 
 agent: Dorothy can you tell me your journey dates? 
 customer: My travelling dates will be from 12/29 till 12/31. 
 agent: Provide me your airport codes? 
 customer: My location codes are from LGA to IAH. Make sure that the connection limit should be 1. 
 agent: No flights were found by your name. Can I help you with anything else? No flights were found by your requirement. 
 customer: That's ok. Thank you for your information. 
 agent: You are welcome.
Output:
no_flight