Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hi. 
 agent: Hello. 
 customer: I am Anthony Brown. 
 agent: How can I help you? 
 customer: I need to book a flight ticket from EWR to DTW, Can you please help me for booking? 
 agent: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates? 
 customer: I would like to travel on 07/06 to return on 07/08. 
 agent: Please give me a moment. 
 customer: Sure. 
 agent: Sorry, no flights are available on your route. 
 customer: Ok, no problem. Thanks for your information. 
 agent: Welcome, have a nice day.
Student:
no_flight