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: Hi. 
 agent: Hello. 
 customer: I am Mary Brown. 
 agent: How may I assist you? 
 customer: I would like to visit Oakland California temple on Aug 17. Can you help me in booking a flight ticket? 
 agent: Sure, I will help you. May I know your source airport code please? 
 customer: My take off airport code is IAH. 
 agent: Do you have any plans on your return journey? 
 customer: Yes, I intend to return on Aug 19. 
 agent: Do you have any specifications? 
 customer: There should be a lay by in between my journey. 
 agent: Mary Brown, no flights has been found on your planned travel dates. 
 customer: Ok, I will check with another agency. Thank you for the information. 
 agent: Thank you for choosing us.
Output:
no_flight