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:       Bob refused all his classmates ' invitations .  
 Person2:I really couldn't understand him .  
 Person1:        He is surely a hard nut , nobody likes approaching him .  
 Person2:We'd better also leave him alone . 

informal