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:       May I take your order now ?  
 Person2:Yes , please . What's special today ? Any special recommendations ?  
 Person1:        Certainly . I would recommend ' Songshuguiyu ' .  
 Person2:The name sounds fascinating . What is it exactly ?  
 Person1:        Well , it is sweet and sour fried Mandarin fish .  
 Person2:Sorry , I'm not interested in vinegar .  
 Person1:        Then , how about this one ?  
 Person2:OK . I'll have that .  
 Person1:        Very good . Could I serve you anything else ?  
 Person2:Thank you . That's enough .  
 Person1:        My pleasure . Just a little while , your order will be ready very soon . Please enjoy your lunch .  
 Person2:Thanks . 

informal