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:       Well , I must be off now . I have an appointment at six .  
 Person2:In that case , I won't keep you any longer . Drop in any time .  
 Person1:        Ok . Goodbye .  
 Person2:See you later . 

informal