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:       I have some photos here taken by myself . Would you like to see them ?  
 Person2:Sure . Speaking of photos , what type of film will be the best ? You know , I'm planning a tour to Jiuzhaigou Valley .  
 Person1:        I would get Fuji 200 film for taking photos of natural beauty .  
 Person2:Thank you so much . You're an expert . 

informal