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:       Mr Brown ! How nice to see you , can I help ?  
 Person2:I'm not exactly sure if it's your department , but I'd like to ask some questions about qualifying for Comprehensive Credit Granting .  
 Person1:        I see . You are one of my favourite customers , Mr Brown . I'm more than happy to help . For Comprehensive Credit Granting , IBA will grant a promised quota for you , that is , if you qualify . Of course , your credit record , within you field of trade needs to be up to scratch .  
 Person2:How long a period will you look at to determine this ?  
 Person1:        We will consider the first part of the year , in your particular field , and your credit rating can be no less than class A , during that period .  
 Person2:That sounds simple enough . It's Friday today , I'll be back on Monday morning , first thing , with all of the relevant data . See you then , and enjoy your weekend . 

informal