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:       Have you bought another handset 
 Person2:No , it is the original one . 
 Person1:        This is silver gray , while I remember your handset was black . 
 Person2:I have changed a case for it . 
 Person1:        Can a handset case be changed ? 
 Person2:Of course . That's why I bought this type . I can change its case frequently , so it is novel to use it . 
 Person1:        How many cases are accessible ? 
 Person2:There are two more , one is orange and the other is pink . I have bought them all . 
 Person1:        It's really going to be fresh all the time . 

informal