Definition: 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
Input: customer: Hi. 
 agent: Hello. How can I  help you? 
 customer: I am planning to go for Boston BOS to meet my parents. So, can you please help me in booking my flight ticket from Detroit DTW? 
 agent: Your travelling dates please? 
 customer: I am planning to start my journey on 09/09 date and I am willing to start my return journey on 09/11 date. 
 agent: May I know your name please? 
 customer: Myself Stephanie Carter. 
 agent: I am sorry no flights found on your route. 
 customer: Ok, fine I can choose other way to complete my trip. Thank you for assisting me. 
 agent: Thank you for choosing us.
Output:
no_flight