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:       Hey Jack . What's going on ? 
 Person2:Hey Matt . I'm going to ask Martha to marry me ? 
 Person1:        Really ? When did you decide this ? 
 Person2:I always knew she was the one , but I decided to pop the big question about 2 weeks ago . I'm just debating on how to do it . 
 Person1:        That's exciting , man . 
 Person2:So how did you propose ? 
 Person1:        You shouldn't use my example . It wasn't special . I kind of wish I made it more special but it's too late now . 
 Person2:What do you think I should do ? 
 Person1:        There are a lot of options . You can surprise her over dinner , or ask her in a public area , or if you have the balls , ask her father in front of her . 
 Person2:I never thought about that . 
 Person1:        Thought about what ? 
 Person2:Asking her father in front of her . How do you think she will react ? 
 Person1:        I don't know . You should know how she's going to react . She is your girlfriend . 
 Person2:I think that's the idea I was looking for . Thanks , man . 
 Person1:        Don't mention it . Good luck . You're going to need it . 

informal