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:       I heard you received a prize for you book . 
 Person2:yes , I did . I won a prize for best local history book at the annual book awards . 
 Person1:        congratulations ! You must be very proud of your achievement . 
 Person2:actually , I was happy just to get the book published . Winning the prize was an added bonus . 
 Person1:        what was the prize ? 
 Person2:I won $ 200 to spend on any books of my choice . 
 Person1:        that ’ s a great prize for a person who writes books ! Have you ever won a prize before ? 
 Person2:I shared a prize with some friends last week . We won a bottle of whisky at a pub quiz . 
 Person1:        I won $ 10 in the lottery last month . Perhaps next time , I ’ ll be luckier and win the jackpot ! 

informal