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'.

Person1: Mary , can you help me set the table ?
Person2:Sure .
Person1: This is usually my chore .
Person2:I don't mind helping .
Person1: We need to set the table for four .
Person2:So that's four plates , four forks , four knives , and four spoons ?
Person1: That's right . Mom didn't know where to buy chopsticks for you .
Person2:Don't be silly ! I know how to use knives and forks .
formal