Detailed 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
Problem:customer: Hi. 
 agent: Hello. How may I assist you? 
 customer: Michelle Johnson here. 
 agent: Nice to meet you Michelle Johnson. 
 customer: I want to book a flight from DCA - DTW to meet a friend, can you help me? 
 agent: Sure, I am here to help you. 
 customer: My travelling dates will be from 04/01 to 04/03. 
 agent: Ok, let me check the flight availability with your preferences. 
 customer: Ok, please check for 1 connection flight. 
 agent: Sorry, there is no flight found on your route. 
 customer: Oh! Thanks for checking. 
 agent: Ok, thanks for contacting us. 
 customer: Most welcome.
Solution:
no_flight