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:       Mum , pass me some more please !  
 Person2:Tina , you should have more nutritious food.Don ' t eat these crisps any more .  
 Person1:        But the ads say they're most nutritious .  
 Person2:Have you ever heard the ads say anything bad about their products ? 

formal