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 . Is anyone sitting here ?  
 Person2:No , nobody .  
 Person1:        You don ’ t mind if I smoke , do you ?  
 Person2:Well , to be frank , yes , I do .  
 Person1:        Oh , I ’ m sorry . But this isn ’ t a no-smoker , isn ’ t it ? I mean would you mind if I smoke here ?  
 Person2:Actually it is . Perhaps you haven ’ t noticed the sign .  
 Person1:        Sign ? What ’ s sign ?  
 Person2:There , on the window .  
 Person1:        Oh , sorry . I didn ’ t notice it . Sorry .  
 Person2:That ’ s all right . 

informal