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:       What's your favourite steps ?  
 Person2:It's hard to say . But I do love waltz very much .  
 Person1:        How about rumba ?  
 Person2:To tell the truth , I don't like it .  
 Person1:        Really ? You must like tango , right ?  
 Person2:Oh , it's really beautiful , but I just can't dance it well .  
 Person1:        Don't be so modest . I'm sure you can dance it very well . Let's dance it now .  
 Person2:OK . I'll have a try .  
 Person1:        Oh , you dance it so well .  
 Person2:Thank you for your compliment .  
 Person1:        I think I'm your lucky fellow . 

informal