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:       Hello , Kevin . I hate to do this , but I have to cancel our appointment .  
 Person2:Oh , no ! Why ? I was looking forward to seeing you at my new place .  
 Person1:        Yeah , I really wanted to come , too . But something unexpected in Shanghai have come up . I have to fly out for a few days , but I'll be back soon .  
 Person2:No problem . Call me when you get back .  
 Person1:        I should have some free time next week . Say , next Wednesday evening ?  
 Person2:That's good for me , but do you think you'll be back by then ? I'd really like to see you .  
 Person1:        Yeah , I'm expecting to come back on Tuesday .  
 Person2:Great ! That's settled then .  
 Person1:        OK . 

informal