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:       Can I get you any dessert ?  
 Person2:Yes , I'd like to try the blueberry pie .  
 Person1:        Excellent choice . ( He brings her the pie . After she finishes , the waiter comes back . ) Would you like anything else ?  
 Person2:No , I'm stuffed . I'm ready for the check .  
 Person1:        Here you are . Thank you and have a nice evening .  
 Person2:Thank you . 

informal