Detailed Instructions: 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'.
Q:  Person1:       Can't you delay your return a little bit ?  
 Person2:No , I can't . I've really got important business .  
 Person1:        Keep in touch then , OK ?  
 Person2:OK . 
A:
informal