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 are you going ?  
 Person2:Take me to the center station , please  
 Person1:        OK , here we go .  
 Person2:Do you think you can get me there seven thirty ?  
 Person1:        We shouldn't have any trouble if we don't get stuck in the traffic jam .  
 Person2:Hope we have good luck .  
 Person1:        Here we are , you still get plenty of time . That's 8.15 $ , please .  
 Person2:Thank you very much . Here's 10 $ , keep the change , please . 

informal