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:       Thank you very much for your invitation .  
 Person2:It's a great honor to have you here , Mr.Brown .  
 Person1:        I'd like to say goodbye to you .  
 Person2:I look forward to seeing you soon.Goodbye ! 

informal