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:       Are you Elvin ?  
 Person2:Elvin Dixon . Who are you ?  
 Person1:        I'm Mary . I want to say I really admire the software you're designed .  
 Person2:Easy stuff . But thanks . And the admiration is mutual .  
 Person1:        It is ?  
 Person2:You're selling invoking subscriptions like nobody's business . And we don't even have a working demo yet .  
 Person1:        I can't take the credit for that . I'm just Zina's assistant . She's the pro . 

informal