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: Excuse me , is this seat taken ?
Person2:Er ... no , go ahead .
Person1: You work upstair , right ? I think I have seen you before . I'm Karren , Karren Brown .
Person2:Nice to meet you , Karren . I'm Tim Wang .
Person1: Happy to know you , Tim .
answer:
informal

question:
Person1: You won one million yuan in a lottery . What will you say ?
Person2:I don't know . I'm too excited to say a word .
Person1: I understand . It's too good to be true , isn't it ?
Person2:Yes , too good to be true .
answer:
informal

question:
Person1: Nice day today , isn't it ?
Person2:Yes , it's beautiful weather we're having .
Person1: We can't complain about the weather recently .
Person2:Yes , the sun shines day after day . It's neither too hot nor too cold .
Person1: I wonder how long this weather can last .
Person2:I hope it will stay fine tomorrow . I'm going to have a picnic with my family .
answer:
informal