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 ? I didn't hear what you said .  
 Person2:I asked you if you wanted some help .  
 Person1:        I am new to this school and not familiar with this library . Can you help me ?  
 Person2:Certainly . What's your topic ?  
 Person1:        I'm looking for information on tropical fish .  
 Person2:All right . You can use the computer over there , enter ' tropical fish'under subject . If you know the title of the book , enter it under ' title '  
 Person1:        Great , thank you .  
 Person2:You are welcome . 

informal