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:       Hi , charlie , are you busy this evening ? 
 Person2:Sorry , I'm afraid that I've got plans tonight . 
 Person1:        What are you doing ? 
 Person2:I'm going to my parents ' house for my father's birthday . 
 Person1:        How old is he today ? 
 Person2:It's his 50th birthday . 
 Person1:        Well , wish him a happy birthday for me . 
 Person2:Sure thing . What are your plans for the evening ? 
 Person1:        I was just thinking of going to a movie tonight . 
 Person2:Well , if you can wait until tomorrow night , I'll go with you then . 
 Person1:        Sorry , I've got people coming over tomorrow night . 
 Person2:Sounds like this weekend just isn't going to work out for us . 
 Person1:        Sounds that way . Maybe some other time then ? 
 Person2:Sure.Hey , I'm sorry , but I've got to get going . 
 Person1:        Yeah , me , too . It's about time I made a move . 
 Person2:Say hello to your friends for me . 
 Person1:        Likewise . See you later . 
 Person2:Bye ! 

informal