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. Timothy White here. 
 agent: Hello, how can I aid you? 
 customer: I am looking for a single connecting flight to Dallas & Fort Worth. Can you book it? 
 agent: Sure, may I know your trip dates? 
 customer: The travel dates for the trip are from 14 Sept to 16 Sept. 
 agent: May I know your journey airport codes? 
 customer: The airport codes are from MSP to DFW. 
 agent: Do you have any preferences? 
 customer: No. 
 agent: Sorry, there is no flight on your given dates. 
 customer: Ok, not a problem. 
 agent: Thank you for opting us.
Output:
no_flight