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:       Good evening , sir . Welcome to our restaurant .  
 Person2:Thank you .  
 Person1:        Do you have a reservation ?  
 Person2:Yes , I do .  
 Person1:        May I have your name , please ?  
 Person2:Yes , it's Mr . Brown .  
 Person1:        Mr . Brown . We were expecting you . This way , please . Will this table be fine ?  
 Person2:Oh , this is just fine .  
 Person1:        Please take a seat .  
 Person2:Thank you .  
 Person1:        Here is the menu . 

informal