{-# LANGUAGE BangPatterns #-}
 
module Main
  ( main
  )
where
 
import           Control.Applicative
import           Control.Monad
import           Control.Monad.ST
import           Data.Bits
import qualified Data.ByteString.Char8         as BS
import           Data.Char
import           Data.List
import           Data.Maybe
import           Data.Ord
import qualified Data.Vector                   as V
import qualified Data.Vector.Mutable           as MV
import qualified Data.Vector.Unboxed           as UV

parse = fst . fromJust
parseInt = parse . BS.readInt
parseInteger = parse . BS.readInteger
readInt = parseInt <$> BS.getLine
readInteger = parseInteger <$> BS.getLine
readIntList = map parseInt . BS.words <$> BS.getLine
readIntegerList = map parseInteger . BS.words <$> BS.getLine


main = do
  s <- getLine 
  print . fst . foldl' update (0, head s) $ tail s

update (count, prv) c = if c == prv then (count, prv) else (count + 1, c)
