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:       Excuse me . May I take a picture of you and your little boy ? 
 Person2:What ’ s it for ? 
 Person1:        It ’ s for a book . 
 Person2:Oh , that ’ s a nice idea . Well , it ’ s fine if you take our picture . 
 Person1:        Thank you . I appreciate your help . 

informal