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 , can I help you ?  
 Person2:Yes , please . I'd like to make a reservation from Hong Kong to Tampa with a stopover in Houston .  
 Person1:        When to leave ?  
 Person2:I would like to leave Hong Kong September the first and leave Houston for Tampa on September the 12th .  
 Person1:        Ok . Can I have your name , please ?  
 Person2:Lily Smith .  
 Person1:        And your telephone number ?  
 Person2:Hong Kong side 3854295 .  
 Person1:        OK . Right then .  
 Person2:Thank you . 

formal