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:       Let me take care of the check today .  
 Person2:Why ? It's unfair . How about going dutch ?  
 Person1:        You paid the last time , because I didn't have any money , remember ?  
 Person2:Oh , come on , I almost forgot . Don't worry about it . I didn't mind picking up the tab last time .  
 Person1:        But you really should let me treat one time , I feel like I own you one if I didn't .  
 Person2:Ok , but it's only for this time .  
 Person1:        What's the damage ?  
 Person2:It's 12 dollars 80 cents all together . But don't forget the tip , it usually 15 % .  
 Person1:        Check , please . 

formal