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:       Do you think my briefcase is big enough to put in all these stuff ? 
 Person2:Let me see . Laptop , flash disk , a ballpoint pen , a pencil , a notebook , a pair of glasses , cell phone , charger , moisture , notion , ... Oh , that is too much . You are not going to a business trip . 
 Person1:        I guess I need all of them . 
 Person2:Actually , the company will provide you with all of these supplies . So , you can leave this very thick notebook at home . 
 Person1:        I know . But it is my lucky charm . I carry it all the time . 
 Person2:Suit yourself . Don ’ t forget to set the alarm clock . 

formal