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:       I'd like to reserve a room .  
 Person2:Which date would that be ?  
 Person1:        For the night of April 18th , for one night .  
 Person2:I'm afraid our hotel is fully booked on that night . Is it possible for you to change your reservation date ?  
 Person1:        No , I'm afraid not .  
 Person2:We might have cancellations . Could you call us again some other day ?  
 Person1:        Sure , but if you do have any cancellations , could you let me know as soon as possible ?  
 Person2:I'm very sorry , sir , but we are unable to do that . We would appreciate it very much if you could call us instead .  
 Person1:        OK , thanks . 

formal