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:       so , how should we go to the theatre ? 
 Person2:let's take the bus . 
 Person1:        I hate the bus system in London ! The bus drivers are rude , the buses are never on time , and there are few people around who can help you . 
 Person2:it's not that bad . You probably just had a bad experience once . 
 Person1:        it wasn't just once . Every single time I take the bus , something bad happens to me or to someone else on the bus . 
 Person2:we could take the subway , but we'd have to go three stops along one line and then change trains twice . 
 Person1:        train fares are twice as expensive as the bus fare , too . 
 Person2:if we don't hurry up , we'll miss the show . Should we take the bus ? 
 Person1:        we're already late , so I think we had better take a taxi . 
 Person2:I don't think we'll be able to find a taxi very easily during hush hours . Let's just take the bus . 
 Person1:        fine . Have a look at the timetable to find out when the next one arrives . 
 Person2:it looks like it should be here in just a few minutes . 
 Person1:        don't worry . Nothing bad will happen . I'll even buy your ticket for you . 
 Person2:thanks , that was nice of you . 
 Person1:        see , now something good has happened to you on a bus trip ! 

informal