Given the task definition and input, reply with output. 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. 
 agent: Hello,. 
 customer: I am Justin Williams. 
 agent: OK Williams, how do you do? 
 customer: I am fine. I have planned for a holiday trip to ATL from JFK, could you help me to search a flight ticket? 
 agent: Sure, its my pleasure to help you. In which dates you are willing to travel? 
 customer: My travelling dates are 12/24 and 12/26. 
 agent: OK, can you please wait a moment. 
 customer: Make sure that 1000 and 1 are my price and connections limits. 
 agent: Sure, I will search for the available flights. 
 customer: OK. 
 agent: Sorry Williams, there is no flight with connection 1 on the dates you provided. 
 customer: Oh! that is fine, do not proceed. Thank you for your help. 
 agent: OK, thank you for reaching us. Have a good day.
no_flight