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 . What time does the next train to London leave ? 
 Person2:At 10:30 . 
 Person1:        Is it a direct train to London ? 
 Person2:Yes , it is . 
 Person1:        OK . Two tickets to London , please . 
 Person2:Single or return ? 
 Person1:        Single , please . How much in total ? 
 Person2:10 pounds . 
 Person1:        Here you are . Which platform should I go to wait for the train ? 
 Person2:It's platform 5 . 
 Person1:        OK . Thank you . 
 Person2:You are welcome . 

informal