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 , Hanson . Today I come to say goodbye to you , for I'm going back to London tomorrow .  
 Person2:No , not so soon . Couldn ’ t I persuade you to stay a couple of days more ?  
 Person1:        Much as I wish to but I really can ’ t . I've already booked the flight .  
 Person2:I hope this won ’ t be our last meeting .  
 Person1:        Of course not . You can come to London to visit me in future . And I also will come here if I have a chance .  
 Person2:I will miss you .  
 Person1:        I will miss you , too . You're really a good friend .  
 Person2:It's a pity that I'm too busy to see you off tomorrow .  
 Person1:        It doesn't matter .  
 Person2:Take care of yourself and remember to keep in touch .  
 Person1:        I will .  
 Person2:Goodbye and have a good flight .  
 Person1:        Thankyou . Goodbye ! 

informal