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 n xs
  | n >= 4 = (solve (n-2) xs)*10 + (xs !! 2)
  | otherwise = xs !! n