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:       When you smell them , they affect your nervous system .  
 Person2:I thought you were supposed to put them in some kind of burner with a candle ...  
 Person1:        You can do that , too . Both methods have a healing effect .  
 Person2:So what's your illness ... shopping fever , sale-itis ?  
 Person1:        Ha-ha ... I'm just fatigued . And tomorrow is a big day .  
 Person2:What's tomorrow ?  
 Person1:        More sales ! 

formal