import Control.Applicative
import Data.List
import Data.Char

getInt :: IO Integer
getInt = (\a -> read a :: Integer) <$> getLine

getIntArray :: IO [Integer]
getIntArray = ((map (\a -> read a :: Integer)) . words) <$> getLine

getStrArray :: Integer -> IO [String]
getStrArray 0 = return [] :: IO [String]
getStrArray n = (:) <$> getLine <*> (getStrArray (n - 1))

countW :: String -> Integer
countW "" = 0
countW ('R':rst) = countW rst
countW ('W':rst) = 1 + countW rst


main = do
    [n, _] <- getIntArray
    flag <- getStrArray n
    print $ foldr (\a b -> b + countW a) 0 flag