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:       Would you talk to me about taking one of Dr . Miller's classes ?  
 Person2:Yes . Have you ever been in one of his classes ?  
 Person1:        I'm thinking about taking his class next semester .  
 Person2:He was a very easy teacher . Are you thinking of taking a class with him ?  
 Person1:        I'm not sure because I really need to learn something , but I also worry about grades .  
 Person2:Grades are important , but don't you think that gaining the knowledge is important , too ?  
 Person1:        I really need to learn this stuff .  
 Person2:He made everything so interesting that the time just flew by . Do you know what I mean ?  
 Person1:        Yes , that sounds right for me .  
 Person2:Did you know that he came here last year after 10 years in the military ?  
 Person1:        Yeah , I already knew that . That could be a good thing .  
 Person2:I think you know that you have to make the best decision for you . Enjoy your year ! 

informal