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:       Good evening , madam . Did you ring for service ? Who can I do for you ? 
 Person2:Yes . The light in this room is too dim . Please get me a brighter one . 
 Person1:        Certainly , madam . I'll be back right away . Do you mind if I move your things ? 
 Person2:Oh , no . Go ahead . 
 Person1:        Thank you . How is the light now ? 
 Person2:It's much better now . Thank you . 
 Person1:        You're welcome . And if you need any other things , please let us know . 
 Person2:Ah , yes , the room is too cold for me . I feel rather cold when I sleep . Can you turn off the air-conditioning ? 
 Person1:        The air-conditioning is already off , madam . 
 Person2:Maybe I'm getting a cold . 
 Person1:        Would you like an extra blanket ? 
 Person2:OK . And would you please get me some hot water , too ? I think I need to take some medicine . 
 Person1:        Certainly , madam . I'll be right back . Here is a blanket and hot water for you . Anything else ? 
 Person2:No , thanks . 
 Person1:        Good night , madam . 

formal