main = do 
    n <- readLn :: IO Int
    {-}
    let day = case n of 
        25 -> "Christmas"
        24 -> "Christmas Eve"
        23 -> "Christmas Eve Eve"
        22 -> "Christmas Eve Eve Eve"
    putStrLn str
    -}
    putStrLn $ getAns n 

getAns :: Int -> String
getAns n 
    | n==22 = "Christmas Eve Eve Eve"
    | n==23 = "Christmas Eve Eve"
    | n==24 = "Christmas Eve"
    | n==25 = "Christmas"


    -- なぜ上のcase文が通らない