import Control.Applicative ((<$>))
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B

main :: IO ()
main = do
  solve <$> B.getLine >>= print

solve :: ByteString -> Int
solve bs = let (Just c) = B.elemIndex 'w' bs
               l = B.length bs
           in min (c - 1) (l - c)