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:       Excuse me , sir.You are not supposed to smoke here . 
 Person2:I beg your pardon ? 
 Person1:        Your seat is in the non-smoking section.So , please refrain from smoking . 
 Person2:Oh , I see.Since I'm a heavy smoker , may I change my seat ? 
 Person1:        Then , I'll try to find a seat in the smoking section.One moment , please . Thank you for waiting . I found a seat in the smoking section for you . 
 Person2:Oh , did you ? Thanks a lot . 

informal