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:       Let ’ s go to WAngFuJing by bus .  
 Person2:Better take the subway . It ’ s faster and more convenient .  
 Person1:        Okay . It will be a new experience for me .  
 Person2:We have a rather comprehensive subway system here . we can get almost anywhere rather quickly on the subway . Especially at this time of a day when the traffic is heavy .  
 Person1:        where do we pay the fare ?  
 Person2:Just give the man standing there three yuan and he'll give you a token . Then you slip it into slot at the turnstile and push the turnstile to get in .  
 Person1:        Let me pay for it .  
 Person2:Where can I get the subway Madam ?  
 Person1:        Ask the worker who sells token to give you one . It ’ s free of charge . Actually maps showing subway routes are posted at most stations .  
 Person2:Do I have to pay additional fare to change train ?  
 Person1:        No , you don ’ t have to . Here comes the train . 

formal