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:       You must like to dance , right .  
 Person2:I'd love to . Do you often come here to dance ?  
 Person1:        Yes , I like the old style dance , such as waltz 、 rumba and so on . They are quite graceful .  
 Person2:You are waltzing quite wonderfully . It's great to dance with a experience and talent partner .  
 Person1:        Thank you for saying . I think you are light on your toes too . Oh , the music starts again , would you like to have another dance , miss ?  
 Person2:Ok , that would be great . Do you like modern dance ? I don't care for it .  
 Person1:        Neither do I . I don't like any kind of modern dances all . 

informal