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:       Do you have any hobbies ?  
 Person2:Yes , I like collecting things .  
 Person1:        Oh , that ’ s interesting , and but what kind of things ?  
 Person2:Several things , for example , Various coins , stamps , stones and so on .  
 Person1:        Stones ? I know many people collecting coins and stamps but stones ?  
 Person2:Yes , stones .  
 Person1:        well , I can ’ t just image it . 

informal