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:       I just dropped in to say good-bye .  
 Person2:What time are you leaving ?  
 Person1:        I'm going to try to leave by ten .  
 Person2:Take care and give my best to your parents .  
 Person1:        Good-bye . Hope to see you soon again next year .  
 Person2:Don't forget to call us if you're in Tokyo . 

formal