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:       Where are you going for lunch ?  
 Person2:I have no idea . I have no appetite .  
 Person1:        I know of a restaurant . I'm sure you'll like it .  
 Person2:Let's go there then . Is it a Chinese restaurant ?  
 Person1:        Yes.it serves excellent Sichuan food . Spicy food may improve your appetite .  
 Person2:I hope so . 

informal