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:       Excuse me . Could you tell me where the post office is ? 
 Person2:Sure . If you get on this road and turn left at the second intersection , you'll see it on your right-hand side . 
 Person1:        Thank you so much for your assistance ! 
 Person2:You are welcome . 

informal