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:       What can I do for you ?  
 Person2:I was looking for a book , but I couldn ’ t find it .  
 Person1:        Did you check our database to see if it was on the shelf ?  
 Person2:I already did .  
 Person1:        Is it on the shelf ?  
 Person2:I didn ’ t see it .  
 Person1:        Apparently somebody took that book out of the library .  
 Person2:Will you ever get another copy ?  
 Person1:        We will definitely be getting another .  
 Person2:Could you please reserve it for me ?  
 Person1:        That won ’ t be a problem .  
 Person2:Thanks . I really appreciate that . 

informal