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:       Want to join me for a midnight snack ? I need to grab something to eat .  
 Person2:Fine with me , but no more chafing dish .  
 Person1:        Let's go the food stall . There's a good one just around the corner .  
 Person2:I'd love to try some snacks .  
 Person1:        ( Later ) Everything looks tempting . What do you want to have ?  
 Person2:Kebabs and roast squid .  
 Person1:        Can I have a bite ?  
 Person2:Help yourself .  
 Person1:        Supper ! 

informal