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:       Where to , madam ?  
 Person2:Grand Central Station , please . I want to catch a 6 p . m . train .  
 Person1:        I think you'll make it if we don't get stuck in a traffic jam .  
 Person2:Here is the Grand Central Station .  
 Person1:        Thank you . How much is the fare ?  
 Person2:The meter reads 9.15 dollars .  
 Person1:        Here you are . Keep the change .  
 Person2:Thank you . 

formal