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: How nice these sunglasses are !
Person2:Yes , they are the latest designs . Would you like to try them on ?
Person1: I want to try on this pair .
Person2:The round shape pair ?
Person1: That's right .
Person2:I think it suits you well .
Person1: I agree , how much ?
Person2:120 yuan .
Person1: It's not expensive . OK . I'll take them .
Example Output: informal

Example Input: Person1: Mrs.Smith , time has stood still with you !
Person2:Thank you.You ' re partial .
Person1: I'm not flattering you.You ' re full of energy every day .
Person2:It's nice to hear that anyway .
Example Output: informal

Example Input: Person1: You know , you really ought to get a new pair of jeans . Those are falling to pieces .
Person2:But this is how I like them , Mum . They ' re just beginning to look right .
Person1: Well , you ' d better get another pair for work at least or you ' re sacking on the spot .
Example Output:
informal