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:       Bill , Happy Halloween ! 
 Person2:Happy Halloween ! What creature are you going to dress up as ? 
 Person1:        I will dress up as a vampire with big fangs . 
 Person2:May I have a look at your costume ? 
 Person1:        Sure . Wait a moment . ( Several minutes later ) Here you are . 
 Person2:I like your black clothes and your fangs are cool . 
 Person1:        I will bite many beautiful girls on the neck tonight . Maybe I will suck their blood . 
 Person2:Haha . Wish you good luck . 

informal