You will be given a definition of a task first, then some input of the task.
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 Christopher Edwards. 
 agent: How may I guide you today? 
 customer: Can you help me to find a flight from MSP to IAD? 
 agent: Sure, I will help you with that. Can you please share your preferable journey dates? 
 customer: My travelling dates are July, 15 and July, 17. 
 agent: Do you have any specifications? I am sorry to say that there is no reservation found under your details. 
 customer: That's fine, thanks for your information. 
 agent: Thank you for reaching us.
Output:
no_flight