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:       How may I help you ?  
 Person2:I need to return these books .  
 Person1:        What happened to this one ?  
 Person2:The cover came off .  
 Person1:        You ’ re going to need to pay for the damage .  
 Person2:How much are you talking ?  
 Person1:        It ’ s going to be $ 5 .  
 Person2:That ’ s not bad at all .  
 Person1:        It really isn ’ t .  
 Person2:Here you go .  
 Person1:        Thank you very much .  
 Person2:You ’ re welcome . Have a nice day . 

formal