{-# LANGUAGE BangPatterns #-}

import Control.Applicative
import Control.Monad
import Data.List
import Debug.Trace (traceShow)
import qualified Data.ByteString.Char8 as B

-- import Data.Array
import Control.Monad.ST
import Data.Array.ST
import Data.Array.Unboxed

inf :: Int
inf = 10 ^ 9 + 7

-- TLE
-- solve :: Int -> Int
-- solve n = (memo ! (n, 0) + memo ! (n, 1) + memo ! (n, 2)) `mod` inf
--   where
--     memo :: Array (Int, Int) Int
--     memo = listArray ((1, 0), (n, 2)) [go i j | i <- [1 .. n], j <- [0 .. 2]]

--     go 1 0 = 0
--     go 1 1 = 1
--     go 1 2 = 0
--     go i 0 = memo ! (i - 1, 1) `mod` inf + memo ! (i - 1, 2) `mod` inf
--     go i 1 = memo ! (i - 1, 0)
--     go i 2 = memo ! (i - 1, 1)

solve :: Int -> Int
solve n = (`mod` inf) $ dp ! (n, 0) + dp ! (n, 1) + dp ! (n, 2)
  where
    dp = runSTUArray $ do
        a <- newArray ((1, 0), (n, 2)) 0 :: ST s (STUArray s (Int, Int) Int)
        writeArray a (1, 1) 1
        forM_ [2 .. n] $ \i -> do
            v0 <- readArray a (i - 1, 0)
            v1 <- readArray a (i - 1, 1)
            v2 <- readArray a (i - 1, 2)
            writeArray a (i, 0) ((v1 + v2) `mod` inf)
            writeArray a (i, 1) v0
            writeArray a (i, 2) v1
        return a

main :: IO ()
main = do
    n <- readLn
    print $ solve n