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:       Mom , I'm starving . 
 Person2:Here are some biscuits . Why are you back so early today ? 
 Person1:        My teacher had a sudden stomachache , so the class was cut shot . You ? 
 Person2:Me what ? 
 Person1:        You are cooking at least two hours earlier than the usual . 
 Person2:It's not for us . 
 Person1:        Then it's for Dad , isn't it ? It's so unfair ! 
 Person2:Don't be a smarty-pants . It's for Grandma Wang . 
 Person1:        What was that again ? 
 Person2:It's for Grandma Wang . She is sick and her only daughter went abroad weeks ago . So she needs our help . 
 Person1:        I'm sorry , I didn't know that . But I wanna help . 
 Person2:Umm , let me think for a moment . We can meet her together after I finish cooking . 
 Person1:        I'll get knee to knee with her . 
 Person2:Good boy . I can only imagine how happy she will be to see you . 

informal