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:       Hello ? This is Mike here . May I have a word with Grace ?  
 Person2:She ’ s not at her desk at the moment . Is there any message I can give her ?  
 Person1:        Yes . Please tell her that tickets to Phantom of the Opera will be delivered in two days . My number is 6521684 0 , extension 236 .  
 Person2:Ok . I ’ ll let her know as soon as possible .  
 Person1:        Thanks a lot . Bye . 

informal