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:       Mary , why don't you come to my house this Saturday ?  
 Person2:I don't know . I'll have to ask my host mom .  
 Person1:        Come on , Mary . This is America . You make your own decisions here .  
 Person2:But I still have to tell her .  
 Person1:        Of course .  
 Person2:Tell you what , give me your phone number .  
 Person1:        It's 555-4321 .  
 Person2:Got it . I'll call you later tonight and we can talk about what to do on Saturday . 

informal