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:       Want to meet for lunch this Saturday ?  
 Person2:Sorry , I can't . I am busy .  
 Person1:        What are you doing ?  
 Person2:I always do volunteer work on the first Saturday of every month .  
 Person1:        What kind of volunteer work ?  
 Person2:I help out at the children's hospital . I help plan activities .  
 Person1:        Oh , yeah ?  
 Person2:Yes , it ’ s exciting . This month we are doing crossword puzzles . 

informal