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:       Hey , Cindy , I ’ m so sorry about yesterday . I shouldn ’ t have yelled at you in front of everyone .  
 Person2:Don ’ t worry about it .  
 Person1:        I don ’ t know what happened to me . I just lost it .  
 Person2:I think you just need to get more sleep .  
 Person1:        Yes , you ’ re right . Good night . 

informal