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:       Good evening , Mr . Frank . Bourbon on the rocks ? 
 Person2:No . This time I'll try Chinese wine . 
 Person1:        What about Mao Tai , one of the most famous liquors in China ? It's good indeed . It never goes to the head . 
 Person2:Do people here drink a lot of liquors ? 
 Person1:        Some do , some don't . Many people in the North are fond of liquors . I think it has something to do with the climate . 
 Person2:Yes , it has . Some Mexicans are crazy . They drink a lot of liquors even on hot days . Have you ever heard of " Tequila Sauta " ? 
 Person1:        Yes , it's a very well-known kind of spirits in Mexico . People drink it with salt and lemon . 
 Person2:Right . It's very strong , just like alcohol . ( Frank sips Mao Tai . ) 
 Person1:        Yes , besides Mao Tai , we have Wu Liang Ye , Fen Jim and so on . 
 Person2:They say that Showing wine tastes quite good . What's it ? 
 Person1:        It's rice wine , a kind of still wine , somewhat like Japanese Sake . Showing is a city in China . 
 Person2:I see . 
 Person1:        By the way , we also have some good red wine and white wine , such as Great Wall White Wine . 
 Person2:Thank you for telling me so much , I'll try them next time . 
 Person1:        I'm always at your service . 

informal