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'.

Ex Input:
Person1: I really dislike reading academic books .
Person2:That may be so , but reading them is an important way to expand your knowledge .

Ex Output:
informal

Ex Input:
Person1: Would you like some more rice ?
Person2:No , thanks . I'm full .

Ex Output:
informal

Ex Input:
Person1: I think it is time to study . Our chemistry exam is coming .
Person2:Oh , I know . When is it ?
Person1: December 1st .
Person2:What's on the test ?
Person1: It seems to be from chapter six to chapter ten .
Person2:Well . I think I'm going to fail my chemistry exam .
Person1: Why are you so pessimistic ?
Person2:I'm not being pessimistic . I'm being realistic . My chemistry is so bad .
Person1: I believe you can pass the exam with good preparation . Don't lose your heart .
Person2:Thank you . That's very nice of you .

Ex Output:
informal