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 today ?
Person2:I need to return a book .
Person1: Can I do anything else for you ?
Person2:I would also like to check out this video .
Person1: Is that all ?
Person2:Yes , just the video .
Person1: May I see your library card ?
Person2:Here you go .
Person1: You have to take care of this video .
Person2:Oh , I will .
Person1: You will be fined if you damage it .
Person2:I understand . Thank you very much .
formal