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:       Oh , my God ! I've been cheated !  
 Person2:What ? What did you buy ?  
 Person1:        It's a brick ! I can't believe how stupid I was . Damn it !  
 Person2:What is it ? Why did you buy a brick ?  
 Person1:        There was a guy on the sidewalk.He had three new boxes , Panasonic video camera boxes.He said he had to get rid of them quick .  
 Person2:And ?  
 Person1:        So he said he'd sell me one for twenty dollars . A four-hundred-dollar camera for twenty bucks .  
 Person2:And it's a brick ?  
 Person1:        Yes .  
 Person2:I can't believe how stupid you are . Why didn't you open the box ?  
 Person1:        I wanted to . But he said , no , the box is still in its plastic wrap from the store.If it's opened , other people won't believe it's new .  
 Person2:So he had the boxes wrapped in plastic .  
 Person1:        Yes , it was the kind of perfect plastic wrap that comes with new products.Look , it even had a bar-code price sticker on it ! It looked brand new .  
 Person2:But why would a guy be selling new video cameras for twenty dollars ?  
 Person1:        He said he had to get rid of them . They were stolen .  
 Person2:Aha ! Now I understand.You were trying to buy stolen goods on the sidewalk.So , what I think is , you deserve to get cheated !  
 Person1:        C'mon , don't blame me ! I thought it was a new camera . We could use it.We were even thinking about buying a camera . I don't understand how he could have such a perfect-looking box .  
 Person2:That's no problem.He just has a friend who works in a shop that can do plastic wrap . That's easy.And probably it's the same shop he got the boxes from.Maybe his friend works in an electronics store . They sell video cameras there . Probably they had a couple video camera boxes lying around.So they get the idea of wrapping bricks to sell to fools like you.Twenty dollars a brick . That's a good profit if they can sell enough bricks .  
 Person1:        You're right , Sarah . I was a fool . I can't believe it . How could I fall for such a trick ? 

informal