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:       Take care , Peter . Don't run so fast.Are you tired ?  
 Person2:Oh , yes . May I sit on the grass ?  
 Person1:        No , you mustn't sit on the grass.Don ' t you see the notes ?  
 Person2:Yes , I can see it.But what's on it ?  
 Person1:        It says Keep off the grass !  
 Person2:Well , there's a bench under the tree.We can sit there .  
 Person1:        Be careful.You can't smoke here .  
 Person2:Why not ?  
 Person1:        Can't you see the notes there ? It says No smoking here . 

formal