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:       How much will it be all together ?  
 Person2:$ 200 , please .  
 Person1:        Can I pay by check ?  
 Person2:I'm afraid you can't , ma'am . We accept only traveler's checks and credit cards .  
 Person1:        OK . How about this card then ?  
 Person2:We can take it . Just a moment ... Please sign here . 

formal