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:       Can you vouch for me that I was with you yesterday ?  
 Person2:Why do I need to do that ?  
 Person1:        My character is in question . Someone was robbed at work and unless I have an alibi , I'm a suspect .  
 Person2:Oh , my goodness . Who do I need to talk to ?  
 Person1:        My employer . Can you come in to the office tomorrow ?  
 Person2:Absolutely . I think I still have the boarding passes from our flight here somewhere .  
 Person1:        That would be the real proof . Didn't we have to show ID to get on the plane ?  
 Person2:Since 911 I think every airline requires that the passengers show ID to board . 

informal