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:       Excuse me . Can you tell me how to find some books on social science ?  
 Person2:Sure . You see all these little drawers here and all the way around the walls ?  
 Person1:        Yes .  
 Person2:These drawers contain cards describing every book in our library . Together they constitute the library's " card catalog " . You can see that each drawer runs from one part of the alphabet to another . Fox example , this drawer goes from SCA to SCM .  
 Person1:        So if I'm looking for a look called A History of Western Society , I'd just look under ' A ' .  
 Person2:No . You'd look under ' W ' . The articles ' a ' and ' the ' don't count in our alphabetization , and cards are generally omitted for extremely common words and phrases such as ' history of ' , ' introduction to ' , ' story of ' and so forth .  
 Person1:        What if I don't know the title of the book ?  
 Person2:Well , you can look under the author's name .  
 Person1:        Could you give me an example ?  
 Person2:Suppose you want to find a book by your professor , William Smith . You'd look under SMITH and then WILLIAM . Since that's very common name , you may have to go through several ' William Smith ' until you come to the one who wrote book on the subject you are interested in . 

formal