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:       Hello , I'm returning your phone call .  
 Person2:I'm glad that you could get back to me so fast .  
 Person1:        No problem , but what were you calling about ?  
 Person2:I needed to talk to you about your son .  
 Person1:        Is he messing up in school ?  
 Person2:He was acting up in class one day last week .  
 Person1:        What was he doing ?  
 Person2:He wouldn't stop talking throughout the class .  
 Person1:        I don't know what's gotten into him .  
 Person2:If you could , would you please talk to him ?  
 Person1:        I will get right on that , and I am very sorry .  
 Person2:I really appreciate your help . 

informal