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: What can I do for you ?
Person2:I want to get a package of cigarette .
Person1: Have you a taste for this kind ?
Person2:No , this kind of cigarette is too strong for me , I desire a mild one .
Person1: What about this ?
Person2:It suits my taste , I'll take it . Do you have lighters ?
Person1: I have a lot of them .
Person2:Show me the one made of plastic .
Person1: OK , here you are .
Person2:Thank you .
Example Output: informal

Example Input: Person1: Hello !
Person2:Is that the box-office ?
Person1: Yes .
Person2:I'd like to book two tickets for the film ' Jane Eyre ' for this evening , please .
Person1: Just a minute please . Oh , I'm sorry , all the tickets for tonight have been sold out .
Person2:What a pity ! How about tomorrow evening ?
Person1: Oh , you're lucky , there are just two tickets left . Do you want to take them ?
Person2:Wonderful , I'll take them .
Person1: OK , your name and telephone number please .
Person2:Wang Min . Telephone number is 13811658 . Can I pick the tickets this afternoon ?
Person1: Yes , of course .
Person2:Thank you very much .
Example Output: informal

Example Input: Person1: Would you like to go to the theater with me tomorrow ?
Person2:Yes , of course . Have you got the tickets ?
Person1: That's coincidence , someone's just returned two tickets and I picked them .
Person2:Matinee or evening ?
Person1: Evening .
Person2:Circle or stalls ?
Person1: Stalls .
Person2:Wonderful , I'll go with you .
Example Output:
informal