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:       John hasn't got married up to now .  
 Person2:Don't you know that he has been carrying a torch for Mary for years ?  
 Person1:        Really ? Does Mary know that ?  
 Person2:Of course not .  
 Person1:        How silly John is . 

informal