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:       Is that girl your girlfriend ?  
 Person2:No , it's not .  
 Person1:        She doesn't look like our classmate .  
 Person2:Don't mistake her as somebody . She ' s my older sister .  
 Person1:        Really , she's so pretty . 

informal