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 hobby ?  
 Person2:Photograph .  
 Person1:        What's the make of your camera ?  
 Person2:Olympus .  
 Person1:        Do you own your own darkroom ?  
 Person2:No , usually I get my films developed at a photo studio , but I make my own enlargements .  
 Person1:        Why ?  
 Person2:Because I can make many different kinds of pictures from one negative . That's more , but that saves money . 

formal