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 maths teacher is rather humorous .  
 Person2:On the contrary , I think he's very serious .  
 Person1:        No , not at all.His examples are really interesting .  
 Person2:So they're easy to remember .  
 Person1:        Yeah , how about your maths teacher ?  
 Person2:He's an old antique , very serious .  
 Person1:        Bad luck , Anne .  
 Person2:Hey ! How about your history teacher ?  
 Person1:        She's another antique .  
 Person2:I'm sorry to hear that . 

formal