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:       There is too much traffic in Taipei these days , I think cars should be banned .  
 Person2:I'm not sure about that . How would people get to work ?  
 Person1:        Well , why not use buses or the MET ?  
 Person2:Well , it may not be that simple . Not everyone likes public transport .  
 Person1:        Why not ? There is nothing wrong with our buses and trains .  
 Person2:Well , I don't often use them , I wouldn't really know . 

formal