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: Could you help me to register for a class ?
Person2:Do you know what class you want to take ?
Person1: Are there any Psychology classes available ?
Person2:I believe there are still two Psychology classes open .
Person1: On what days are the classes ?
Person2:There is one class on Tuesday and Thursday from 2 to 4 .
Person1: Can you tell me about the other class ?
Person2:It's from 10-12 on Monday and Wednesday .
Person1: You're positive that these are the only classes left ?
Person2:These two are the only ones .
Person1: The class on Monday and Wednesday will be fine .
Person2:Very good .
formal