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:       Hey , you have been promoted to president of the department .  
 Person2:All this is thanks to the efforts of my superiors and colleagues .  
 Person1:        You are so smart . Your efforts in the success of the plan were outstanding .  
 Person2:I just did what I should have done .  
 Person1:        You ’ Ve got a great personality .  
 Person2:Thank you for your compliments . I will try even harder to repay the company and your support .  
 Person1:        I believe you will . I ’ m very pleased with your work . Your promotion will contribute to the development of the company .  
 Person2:Thanks for saying so . 

informal