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:       What can I do for you ? 
 Person2:I want to get a package of cigarette . 
 Person1:        Have you a taste for this kind ? 
 Person2:No , this kind of cigarette is too strong for me , I desire a mild one . 
 Person1:        What about this ? 
 Person2:It suits my taste , I'll take it . Do you have lighters ? 
 Person1:        I have a lot of them . 
 Person2:Show me the one made of plastic . 
 Person1:        OK , here you are . 
 Person2:Thank you . 

informal