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 .
Output:
informal