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:       Well , Miss Li , it's time for us to say good-bye to each other . 
 Person2:Yes , I suppose we must . I have enjoyed all these days that you have spent with me , and I'll always remember them . I've learned a lot from you . Thank you for all your kindness . 
 Person1:        I'm glad you could come to see us off . I have enjoyed your interpreting . You have done a wonderful job . I hope you be my interpreter again next time I'm here . 
 Person2:I hope so , too . 
 Person1:        It's hard to tear myself away from your friendly people and your ancient country , but nothing lasts for ever . I have to go back home this time , but I'm sure I'll return very soon . 
 Person2:I'm really glad to hear that 
 Person1:        Good-bye . Miss Li , say hello to your husband and your son for me . See you soon . 
 Person2:Good-bye , Mr White . A happy journey home , and hope to see you again soon . 

informal