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:       Can you tell me the best way to see the city ?  
 Person2:Sure , I advise the sightseeing buses .  
 Person1:        Travel by the buses ? That sounds interesting .  
 Person2:Yes of course.You can see the whole city on the bus . It's cheap as well as efficient .  
 Person1:        Oh , there comes the bus . 

informal