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:       Why did you buy that painting ? 
 Person2:I think it's beautiful . I want to hang it in the living room . 
 Person1:        It looks like some kind of mistake . 
 Person2:That's the beauty of it — the imperfection . 
 Person1:        Oh . Who is the artist ? 
 Person2:Your daughter . She sold it at the school auction . 
 Person1:        Oh ! How about we hang it over here where everyone can see it ? 
 Person2:I guess you see the value in it , too . 

informal