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 do you think of smoking ?  
 Person2:It's harmful . Not only for yourself but for others .  
 Person1:        What in your opinion can be done to stop smoking ?  
 Person2:Stop producing cigarettes .  
 Person1:        But that'll affect the national economy .  
 Person2:That's right.But I don't think there are better ways .  
 Person1:        How about printing a warning on each cigarette packet ?  
 Person2:Maybe it can take effect . 

formal