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:       Where do you have to go . 
 Person2:To New York . 
 Person1:        When do you have to be there . 
 Person2:Tomorrow morning . 
 Person1:        How long do you have to be there ? 
 Person2:Three days . 
 Person1:        When will you be back ? 
 Person2:On Friday . 

formal