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's the matter ?  
 Person2:Which subway should I take to get to the East Side ?  
 Person1:        Oh , you have to take the shuttle to Grand Central .  
 Person2:Which train is that ? Which platform does it leave from ?  
 Person1:        It's not on this platform . These trains are uptown and downtown , not crosstown . You have to go up these stairs over there . 

formal