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:       May I help you ?  
 Person2:I would like to return this book .  
 Person1:        May I do anything else for you ?  
 Person2:I would also like to check out these books .  
 Person1:        Will that be all ?  
 Person2:That ’ s it .  
 Person1:        Do you have your library card ?  
 Person2:Oh , yeah . Here you go .  
 Person1:        Will that be all for today ?  
 Person2:That ’ ll be all .  
 Person1:        These books are due back in two weeks .  
 Person2:Thanks . Have a good one . 

informal