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:       Will you bring our bill , please ?  
 Person2:Yes , certainly . I'll be back in a minute . Here you are  
 Person1:        Thanks.Let me see . I think there's a mistake on the bill here.Would you mind checking , please ?  
 Person2:Of course , not.Let me check.Oh , you seem bo be correct .  
 Person1:        How about tax and service charge ?  
 Person2:Only ten percent tax is included in the bill .  
 Person1:        Then one hundred U . S . dollars covers everything , doesn't it ?  
 Person2:It sure does . 

informal