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:       Are you free on the thirteenth in the afternoon ?  
 Person2:No I'm afraid not . I'm meeting Ruth then . How about the fourteenth in the morning ?  
 Person1:        I'm sorry . I'm attending a meeting at the Hilton then .  
 Person2:What about the next day ?  
 Person1:        No . I'm busy then too . I'm meeting Dorothy Heath at North Bridge Road . Are you free on Thursday afternoon ?  
 Person2:Yes , I think I am . Let's meet for lunch at mouth restaurant .  
 Person1:        Good idea ! Is two o'clock okay ?  
 Person2:That's fine . See you there ! 

informal