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:       Well , sir , we are asking all our guests to wear a jacket and a tie in our restaurant .  
 Person2:Is that so ? I didn't know it.Can I possible borrow a jacket and a tie ?  
 Person1:        I'm sorry you can't borrow a jacket and a tie .  
 Person2:Then we return to the hotel and come back.Will you change the appointment ?  
 Person1:        Certainly.What time will you come back ?  
 Person2:At seven , please .  
 Person1:        How many in your party ?  
 Person2:A party of three .  
 Person1:        All right.We are waiting for you at seven . 

formal