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:       isn't it wonderful walking here ?  
 Person2:what do you mean ?  
 Person1:        I mean look at all these magnificent tall buildings around us .  
 Person2:yes , look over there . That's the Empire State Building . My book says it's 102 stories tall .  
 Person1:        it's quite famous but don't you think it looks a bit old-fashioned ?  
 Person2:you're right , but when it was built in 1930 it was a marvel of technology and engineering .  
 Person1:        what other important buildings are we going to see on Fifth Avenue ?  
 Person2:quite a number . Actually every skyscraper has a history . A few blocks ahead we'll see St.Patrick ' s Cathedral and just across the street will be the world-renowed Rockefeller Center . It's a landmark  
 Person1:        what's there after that ?  
 Person2:well then , there's a Central Park . Facing the park on Fifth Avenue is probably some of the most expensive properties in the world .  
 Person1:        what are all they for ?  
 Person2:most of them are office buildings , huge department stores , and hotels but some are just private homes . New York is one of the financial centers of the words so there are lots of very expensive places . 

informal