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 .  
 Person2:Hi , Lucy , are you free to talk ?  
 Person1:        Not really , I ’ m in a meeting . Can I call you back in ... say ... 15 minutes ?  
 Person2:Sure , speak to you later . It isn ’ t urgent . Maybe it is easier if I send you an e-mail .  
 Person1:        Ok , I ’ ll look out for it . Sorry , I can ’ t talk now . 

informal