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: Would you and your wife care to come to our place and have tea with us some afternoon ?
Person2:Why , that's very kind of you , Mrs . Johnson . I'm sure my wife will be glad to .
Person1: How about tomorrow afternoon ?
Person2:Tomorrow afternoon would be fine .
informal