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:       We're leaving now .  
 Person2:Here's your bill .  
 Person1:        Right . And would you please forward our mail to this address ?  
 Person2:Certainly .  
 Person1:        Thank you . Goodbye .  
 Person2:Goodbye . Hope to see you again . 

informal