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 went to Super Junior's concert last night . It was fantastic .  
 Person2:Really ? Their songs are very popular all round Asia now . I am also a big fan of theirs .  
 Person1:        Yes , their new album just came out last week . It is number one on the billboard .  
 Person2:I really love their dancing . They are all excellent dancers .  
 Person1:        The lyrics of the new song are beautiful , too . Can you sing ?  
 Person2:Sure . I think you can hear the song everywhere you go now .  
 Person1:        Let's go buy their new album . Want to come with me ?  
 Person2:Why not ? 

informal