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'.

Example 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 .
Example Output: formal

Example Input: Person1: I am not convinced by your explanation . Could you explain it ?
Person2:Sorry , I really can't do that . There's little time left for us .
Person1: I can't accept your excuse . It's five o'clock .
Person2:Yeah . But I have an appointment with Ann .
Person1: Ok , sounds good . But I think it's your trick .
Example Output: informal

Example Input: Person1: Why , Tom ? It's five to six already and you are still writing here .
Person2:So what ? Are we going anywhere ?
Person1: Yes , have you forgotten ? We have arranged to go to Mary's to watch some videos tonight .
Person2:Oh , I'm sorry I forgot all about it.Well , can I take a rain check ?
Person1: What's the matter with you ? You are the one that persuaded all of us to go there .
Person2:I'm terribly sorry , Rose.But I have to finish this paper by tomorrow or professor Martin will kill me .
Example Output:
formal