Given the task definition and input, reply with output. 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: What can I do for you ?
Person2:I ' m returning these books .
Person1: Let me have them .
Person2:Here are all of them .
Person1: These books are two weeks late .
Person2:I didn ' t have time to return them .
Person1: You ' re going to have to pay late fees .
Person2:How much ?
Person1: 25 cents a day .
Person2:25 cents a day ?
Person1: That means 25 cents for each late book .
Person2:That ' s expensive .
informal