{-# LANGUAGE OverloadedStrings #-}
import Control.Applicative
import qualified Data.Text as T

solve :: T.Text -> T.Text
solve s =
  if s == s''' then s else solve s'''
  where s' = T.replace "SSSTTT" "" s
        s'' = T.replace "SSTT" "" s'
        s''' = T.replace "ST" "" s''

main = do
  s <- T.pack <$> getLine :: IO T.Text
  print $ T.length $ solve s
