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:       How can you keep in touch with your aunt in America ? 
 Person2:Oh , I make a phone call once a month . 
 Person1:        It's very expensive , right ? 
 Person2:Yeah . 
 Person1:        Why not send E-mail through the Internet ? 
 Person2:Is it convenient and cheap ? 
 Person1:        Sure . You can send E-mail to each other every day through the internet . In addition , you can make a phone call through the internet , too . 
 Person2:Really ? I'm so glad to hear that.But I don't know how to get access to the Internet.Could you show me ? 
 Person1:        No problem . I'll tell you . 
 Person2:I'll appreciate it very much . 

informal