You will be given a definition of a task first, then some input of the task.
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'.

Person1: Where should I sit ?
Person2:Why don't you sit in the back with me ?
Person1: Okay .
Person2:By the way , what's your last name ? I forgot what it is .
Person1: It's Lin . It's spelled L-I-N .
Person2:R-I-N ?
Person1: My pronunciation is not very good . It's L-I-N , Lin .
Person2:I got it . Mary Lin .
Person1: Lin is a common Chinese last name .
Output:
formal