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've got a complaint about the noise next door . 
 Person2:Yes , it's most irritating . 
 Person1:        Some people aren't very considerate . 
 Person2:We're going to do something about it . 
 Person1:        Yes , I think so . 
 Person2:We can't put up with it any more . 
 Person1:        We'll play the CD loud , is that all right ? 
 Person2:I don't think so . 
 Person1:        What should we do ? 
 Person2:Why don't we call them ? 
 Person1:        Good idea . 

formal