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 hear scientists in the US have discovered a new AIDS vaccine .  
 Person2:Does it work ?  
 Person1:        I don ’ t know . The report says it is better than the old vaccines .  
 Person2:Don ’ t count on it . I think the best way to prevent AIDS is to keep yourself clean by having clean sex and keeping a regular sex partner .  
 Person1:        Right . That ’ s why doctor say AIDS prevention means cleanness . 

formal