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:       I want some envelopes please . 
 Person2:Do you want the large size , or the small size ? 
 Person1:        The large size please . Do Have you any writing-paper ? 
 Person2:Yes , we do . I don't have any small pads . I only have large ones . Do you want a pad ? 
 Person1:        Yes , please . And I want some glue . 
 Person2:A bottle of glue . 
 Person1:        And I want a large box of chalk , too . 
 Person2:I only have small boxes . Do you want one ? 
 Person1:        No , thank you . 
 Person2:Is that all ? 
 Person1:        That's all , thank you . 
 Person2:What else do you want ? 
 Person1:        I want my change . 

formal