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:       Why you are so crazy about Beijing Opera ? It's so boring .  
 Person2:But I think it's fantastic and charming . Well , you have your opinion and I have mine .  
 Person1:        Maybe you're right . But I just still can't understand ...  
 Person2:Come on . I don't see any point in arguing about this . Everyone has a right to his own opinion . 

informal