modulo :: Int
modulo = 1000
{-# INLINE modulo #-}

type Number = (Int, Int)

infixr 8 @^@
infixl 7 @*@
(@*@) :: Number -> Number -> Number
(ap, aq) @*@ (bp, bq) = ((ap * bp + 3 * aq * bq) `mod` modulo, (ap * bq + aq * bp) `mod` modulo)
{-# INLINE (@*@) #-}

(@^@) :: Number -> Int -> Number
a @^@ i
  | i == 0    = (1, 0)
  | odd i     = res @*@ a
  | otherwise = res
  where
    res :: Number
    res = (a @*@ a) @^@ (div i 2)
{-# NOINLINE (@^@) #-}

main :: IO ()
main = do
  n <- readLn :: IO Int
  let x = (1, 1) @^@ n
  print $ if even n then ((fst x) * 2 - 1) `mod` modulo else ((fst x) * 2) `mod` modulo