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:       Mark , you are not telling me the truth . Now why ? 
 Person2:Promise you are not going to be angry ? 
 Person1:        Yes , all right . So why ? Go on then . Say it . Oh , really , Mark . I promise I'm not going to be angry . Now why were you late ? 
 Person2:I forgot . 
 Person1:        You forgot ? You ... 
 Person2:Ah , ah , you promised , and remember ? 

informal