import Data.List

main = do
  cs <- getLine
  print $ compute cs

compute cs = if null lens then -1 else head lens where
  lens =
   [ length as + length cs + 3
   | ('c':xs) <- tails cs
   , let (as,bs) = break ('w' ==) xs
   , not $ null bs
   , let (cs,ds) = break ('w' ==) $ tail bs
   , not $ null ds
   ]