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 are your hobbies , Mr . Green ? 
 Person2:I like collecting stamps . 
 Person1:        But it's an expensive hobby , isn't it ? 
 Person2:Yes , you're right . What do you like to do in your spare time ? 
 Person1:        I usually play chess with my friends . But I like playing basketball best . 
 Person2:Do you play basketball well ? 
 Person1:        No , I'm not very good at it . I play just for the fun of it . 
 Person2:Shall we have a game together some day ? 
 Person1:        OK , that'd be very nice . 

informal