import Control.Arrow ((&&&))
import Data.List (group)

data Winner = East | West | NA deriving (Eq, Ord, Show, Read)

freq :: Ord a => [a] -> [(Int, a)]
freq = map (length &&& head) . group

judge :: String -> Winner
judge = f . dropWhile (\x -> fst x < 3) . freq
    where
        f xs
            | null xs = NA
            | (snd . head $ xs) == 'O' = East
            | otherwise = West

main :: IO ()
main = print . judge =<< getLine