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:       Room service.What can I do for you ?  
 Person2:Excuse me . Can you tell me where l can buy a notebook and a pen ? I need them badly .  
 Person1:        Here is a shop in the hotel . It's on the 11th floor .  
 Person2:That's quite convenient.Well , would you please buy me some ? I am so busy.My room number is 304 .  
 Person1:        Certainly . 

formal