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:       You'd better prepare for the examination .  
 Person2:I don't think the exam will be very hard .  
 Person1:        You should change your attitude , or you will not pass the course .  
 Person2:Maybe you're right . I have been too lazy lately . 

informal