Definition: 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'.
Input:  Person1:       Could you tell me how to use the library ? 
 Person2:Sure . All you need is your student ID card or admission card to check out books and read journals or magazines in the library . 
 Person1:        How many books am I allowed to check out at a time ? 
 Person2:Two books at a time . Except magazines or journals , they have to be read within library . 
 Person1:        How long can I keep the books ? 
 Person2:For one month . If you can ’ t return the books in time , you'll be fined . But if you renew them , you can keep them longer . 
 Person1:        I see . Now I want to check out two books on spoken English . Can you show me where I can find them ? 
 Person2:Yes , just over there to your right . 
 Person1:        Thank you very much . 
 Person2:You ’ re welcome . 

informal