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:       Excuse me , Miss .  
 Person2:Yes . May I help you ?  
 Person1:        I'm a graduate student here in mathematics . I've just come from China and I've never used a western library before . I'll be here for five years , so I'd like to learn to use the library as efficiently as possible . I wonder if someone might have time to show me around .  
 Person2:I'd be very glad to show you around , but I'm very busy right now.Could you come back about 3,30 ?  
 Person1:        Sure . 3:30 this afternoon .  
 Person2:Good . See you later .  
 Person1:        Thank you . Good-bye . 

informal