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:       I need to buy a bus pass .  
 Person2:What kind of bus pass would you like to buy ?  
 Person1:        What are the different kinds ?  
 Person2:You can get a day , weekly , monthly , or student pass .  
 Person1:        Could I get a student pass , please ?  
 Person2:Sure , can I see your student ID ?  
 Person1:        Sure , here it is .  
 Person2:Very good .  
 Person1:        How much for the pass ?  
 Person2:It's free , but the monthly sticker is $ 24 .  
 Person1:        Okay , I'll take it .  
 Person2:Thank you for your purchase .  
 Person1:        You are welcome . 

informal