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:       Our philosophy teacher is very humorous .  
 Person2:I usually have the wrong notion that he's very serious .  
 Person1:        No , not at all.The examples he gives are very interesting .  
 Person2:No wonder when I pass your room , I always hear your laughter . 

informal