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:       Hi , I want to see the Terra Cotta Warriors in Xi'an . Could you please remind me when we are arriving at that stop ?  
 Person2:Oh . You took the wrong bus . You need to take Bus 151 which goes the opposite direction .  
 Person1:        Oh , no ! What should I do now ?  
 Person2:Don't worry . You can get off at the next stop and walk across the street and take the Bus 151 to the opposite direction .  
 Person1:        Ok . How many stops do I have to go ?  
 Person2:About 15 stops .  
 Person1:        That is a long way to go . It is so kind of you to help me . Thank you very much .  
 Person2:My pleasure . 

informal