instruction:
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'.
question:
Person1: Here's 30 yuan for my ticket .
Person2:Keep it . I'm buying tonight .
Person1: No , you can't do that .
Person2:Sure I can , my treat .
answer:
informal

question:
Person1: Good to see you . Come on in .
Person2:Thank you . Here's a present for you .
Person1: Oh , you shouldn't . But thank you very much .
answer:
informal

question:
Person1: You are starting to learn English ?
Person2:Yeah . I like it , Dad .
Person1: You ' re lucky you start to learn it so easily . I learned English very late , and learned it all by myself . At that time we didn ' t have a good English studying environment . I have to keep my dictionary on hand .
Person2:Really ?
answer:
informal