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:       So , where are you going to spend your winter vacation ?  
 Person2:Oh , I ’ m going to meet my girlfriend in Thailand .  
 Person1:        You have a girlfriend in Thailand ? Interesting . How come I have never heard of that ?  
 Person2:Actually it will be my first time to meet her .  
 Person1:        You mean you haven ’ t seen her before ? Then , how could she be your girlfriend ? Maybe you don ’ t even know her .  
 Person2:That ’ s true . But we have known each other over the Internet for a few months now . Actually we are on an intimate level . We even plan to be engaged next month .  
 Person1:        Congratulations ! It ’ s good to follow your heart . But I just didn ’ t expect to be so fast .  
 Person2:The Internet is making interaction much faster . People are getting to know each other much more quickly this way .  
 Person1:        Probably you ’ re right . 

informal