{-# LANGUAGE BangPatterns #-}
import           Control.Monad
import           Data.IORef
import qualified Data.Vector.Fusion.Stream.Monadic as VFSM
stream :: Monad m => Int -> Int -> VFSM.Stream m Int
stream !l !r = VFSM.Stream step l
  where
    step x
      | x < r     = return $ VFSM.Yield x (x + 1)
      | otherwise = return $ VFSM.Done
    {-# INLINE [0] step #-}
{-# INLINE [1] stream #-}
r09 :: Monad m => (Int -> m ()) -> m ()
r09 = flip VFSM.mapM_ (stream 0 10)
{-# INLINE r09 #-}
r19 :: Monad m => (Int -> m ()) -> m ()
r19 = flip VFSM.mapM_ (stream 1 10)
{-# INLINE r19 #-}
r03 :: Monad m => (Int -> m ()) -> m ()
r03 = flip VFSM.mapM_ (stream 0 4)
{-# INLINE r03#-}
main :: IO ()
main = do
  n   <- readLn :: IO Int
  ans <- newIORef (0 :: Int)
  tmp <- newIORef (0 :: Int)
  r19 $ \i -> r09 $ \j -> do
    writeIORef tmp (i * 10 + j)
    temp <- readIORef tmp
    when (temp <= n && temp `mod` 3 == 0) $ modifyIORef' ans succ
  r03 $ \i0 -> r03 $ \i1 -> r03 $ \i2 -> r03 $ \i3 -> r03 $ \i4 -> r03 $ \i5 -> r03 $ \i6 -> r03 $ \i7 -> r03 $ \i8 -> do
    writeIORef tmp (i0 + i1 * 10 + i2 * 100 + i3 * 1000 + i4 * 10000 + i5 * 100000 + i6 * 1000000 + i7 * 10000000 + i8 * 100000000)
    modifyIORef' tmp (*3)
    temp <- readIORef tmp
    when (temp <= n && temp > 100) $ modifyIORef' ans succ
  print =<< readIORef ans