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
Input: customer: Hi. 
 agent: Hello. 
 customer: Sandra Phillips here. 
 agent: How may I assist you? 
 customer: I would like to travel Las Vegas to meet my grandfather, can you please book a flight ticket from EWR to LAS? 
 agent: Sure, may I know your travel dates? 
 customer: Ok, my planned dates of journey are 10/07 and 10/09. 
 agent: Do you have any specifications? 
 customer: Please check for a connecting flight. 
 agent: There is no flight on your details. 
 customer: Ok, no problem. 
 agent: Thank you. 
 customer: Thank you so much.
Output:
no_flight