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:       Eric , how long will you be in China ? 
 Person2:I don't know . Well , my contract here is for one year , and I don't know what I should do after that . Maybe going around for a while . 
 Person1:        Well , have you ever thought about learning some Chinese ? 
 Person2:Actually , I am learning that now . But it's too hard for me . You know the four tones and the stuff . It really freaks me out . 
 Person1:        Don't worry . All things are difficult before they are easy . 
 Person2:You hit the nail right on the head . 
 Person1:        Well , are you invested in some language-exchange program ? 
 Person2:What is it ? 
 Person1:        It's where I teach you Chinese , and in exchange you teach me English . 
 Person2:Awesome . I've been giving this a lot of thought . When can we do this ? 
 Person1:        How about this sunday ? 
 Person2:Ok , cool . 
 Person1:        Good . I'll give you a call tonight . 
 Person2:No problem . 
 Person1:        Bye . 

informal