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'd better be going .
Person2:So soon ? Why don't you stay a little longer ?
Person1: I wish I could , but it's already late .
Person2:Oh , it's a pity that you have to leave .
Person1: Thank you for a wonderful meal .
Person2:I'm glad you enjoyed it .

Ex Output:
informal

Ex Input:
Person1: Do you like a package tour or to travel alone ?
Person2:I prefer a package tour , and we don't have to worry about accommodation , meals or that sort of trivial demanding things .
Person1: I prefer travel alone . I'll have a lot of time lingering at one place .

Ex Output:
formal

Ex Input:
Person1: It's awfully quiet around here .
Person2:Yeah . There's nobody in sight .
Person1: I have a feeling that we're not supposed to be in here .
Person2:I think you're right . Let's go .

Ex Output:
informal