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 . May I come in ?  
 Person2:Come in please .  
 Person1:        Mr . Green ?  
 Person2:Yes . Put them on there please .  
 Person1:        OK.If you need anything , just call the Room service .  
 Person2:Thank you . By the way , what shall we do with the plates when we finish our meal ?  
 Person1:        Just leave them outside the door . We will take care of it .  
 Person2:I see . Thanks a lot . 

formal