Definition: 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'.
Input:  Person1:       I've brought some potato chips . Would you like some , Jack ?  
 Person2:Yes . I'd like to swap some of my peanuts for your chips .  
 Person1:        That'll be fine . Thanks .  
 Person2:Do you have any ketchup ?  
 Person1:        I forgot to bring it , but maybe Mary has some . Let's go and ask her . 

informal