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:       May I have an appointment with you tonight ?  
 Person2:Very sorry , I am occupied tonight . What about tomorrow night ?  
 Person1:        OK . where and when ?  
 Person2:7:00 in my staying hotel .  
 Person1:        OK , I am going to the hotel to pick you up . See you tomorrow night . 

informal