import Control.Monad
import Control.Applicative
import Data.List

main = do
  t <- readLn

  putStrLn . show $ solve t [0,0,1,7,7,7,9,9,9,9]

solve :: Int -> [Int]-> Int
solve 2 xs = 1
solve n xs
  | n > 9 = (xs !! 9)*10 + solve (n-9) xs
  | n >= 4 = (xs !! (n-2))*10 + solve (n-2) xs
  | otherwise = xs !! n