import qualified Data.ByteString.Char8 as BS
import Data.Maybe

readInt = fst . fromJust . BS.readInt

readIntList = map readInt . BS.words

getIntList = readIntList <$> BS.getLine

main = do
  [l, r, d] <- getIntList
  print $ r `div` d - (l - 1) `div` d
