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:       Excuse me , I'm a little lost . Which bus do I take to get to Shi Da ?  
 Person2:Let's see . From here , you have to take the 278bus .  
 Person1:        Oh ok , where do I get off ?  
 Person2:You should get off at the first Shi Da stop .  
 Person1:        Ok , thanks ...  
 Person2:You're new at this , huh ?  
 Person1:        No , is it difficult ?  
 Person2:No , it's quite simple . When you get on , just ask the bus driver when to pay the fare and where you want to get off .  
 Person1:        How much does it cost ?  
 Person2:Only 15 NT per section . Oh look , that is your bus .  
 Person1:        Wow , I can't thank you enough .  
 Person2:Don't mention it . 

informal