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:       I know you are a good dancer . What dances do you like ?  
 Person2:I like the old styles of dance . Such as fox-trot , waltz , rumba , tango and so on . They're all graceful .  
 Person1:        Why do you like old styles of dance ?  
 Person2:Why not ? Do you think I should like modern dance ?  
 Person1:        I think so , because most young people like modern dances , such as rock and roll .  
 Person2:Oh , sorry . I don't like them . Why not ask Lily . She likes modern dance .  
 Person1:        OK , I will.Thank you . 

informal