import Control.Monad

main :: IO ()
main = do
    [n, _] <- map read . words <$> getLine :: IO [Int]
    as <- replicateM n getLine

    let ans = solve as
    print ans

solve :: [String] -> Int
solve as = solve_rec as 0
    where
        solve_rec [] c = c
        solve_rec (a:as) c = solve_rec as (c + count a 'W')
        
        count a ch = count_rec a ch 0
        count_rec [] _ n = n
        count_rec (a:s) ch n = count_rec s ch (n + if a == ch then 1 else 0)