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:       John , have you ever watched Beijing Opera ?  
 Person2:Yes , I watched once .  
 Person1:        What do you think of it ?  
 Person2:Well , honestly speaking , I went to watch it out of curiosity . I'd say it's really a special art form .  
 Person1:        I couldn't agree more . Actually , I'm a Beijing Opera fan .  
 Person2:Really ? Good for you . 

informal