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 ! So you are leaving today . 
 Person2:Hello . Thank you for seeing me off . You actually don't need to bother . 
 Person1:        It is my pleasure to see you off . 
 Person2:Thanks a lot . I hope to see you again . 
 Person1:        I hope so , too . 
 Person2:Thanks again for everything you have done for me . 
 Person1:        You're welcome . Have a nice trip ! 

informal