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:       It ’ s very kind of you to invite me to dinner .  
 Person2:Please sit down and make yourself at home . Please don ’ t stand on ceremony .  
 Person1:        This dish is really delicious .  
 Person2:I ’ m glad that you like it . This is only the first time that I made it .  
 Person1:        You ’ re great . Could you say it in Chinese ?  
 Person2:Sure , we call it doubt . 

informal