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:       Oh ! You're engaged ! What a beautiful engagement ring ! Who to ?  
 Person2:Of course Mike . Who else ? We fell in love at first sight .  
 Person1:        When's the wedding going to be ?  
 Person2:We haven't decided yet . There are a lot of things to sort out , you know .  
 Person1:        Are you having a big wedding ?  
 Person2:Yes , I've always dream of having a big wedding .  
 Person1:        But what do you say about that ?  
 Person2:I don't really enjoy big occasions , but I think I ’ ll come round to the idea in the end , It only happens once in a lifetime .  
 Person1:        Perhaps I'll agree with Mike . I couldn't stand a big wedding with many relatives and friends of my parents or my wife whom I'd never met before . 

informal