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:       Do you want to rent a car ? 
 Person2:Yes , I want one with automatic transmission . 
 Person1:        I think that one fits you . Do you need insurance ? 
 Person2:Full insurance , please . 
 Person1:        OK , by the way , fill the gas tank when you return the car . 

formal