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:       May I invite you for a dance ? 
 Person2:With pleasure . 
 Person1:        You dance well . Do you breakdance ? 
 Person2:Me , what brought that on ? 
 Person1:        There's a story about breakdancing in the paper . 
 Person2:What does it say ? 
 Person1:        According to the story , it's some sort of modern dance style . 
 Person2:Like disco ? 
 Person1:        Well , breakdancing is more a physical exercise than a dance . 
 Person2:And disco a kind of nightclub . 
 Person1:        Right , a disco is a place where people dance according to nonstop recorded music ... 
 Person2:So ... disco is what the music is called and a disco is a place where people go to dance to it.And breakdancing is a different sort of thing altogether . 
 Person1:        You are witty . 

informal