Definition: You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. You are required to assign a label 'formal' if there is an absence of emotion and a presence of questions anywhere within the conversation. If such pattern is not found assign the label 'informal'.
Input:  Person1:       Excuse me . What time does the next bus for Boston leave ? 
 Person2:It leaves at 8: 30 . 
 Person1:        I see . Are there any seats available ? 
 Person2:Just a moment , please . Yes , you can have a seat . 
 Person1:        Good . How much is a one-way ticket ? 
 Person2:It's 38 dollars . 
 Person1:        All right . Here's 40 dollars . 
 Person2:Here's your ticket and change . 
 Person1:        Thank you . Which gate should I go to for the bus ? 
 Person2:Go to gate number 2 , please . 
 Person1:        Thank you very much . 
 Person2:Don't mention it . 

informal