import qualified Data.ByteString.Char8 as SC
import qualified Data.ByteString.Lazy.Char8 as LC
import Data.Maybe (fromJust)

unsafeReadInt :: LC.ByteString -> Int
unsafeReadInt = fst . fromJust . LC.readInt

computeMaxNum :: Int -> SC.ByteString
computeMaxNum n
    | even n = SC.replicate d '1'
    | otherwise = SC.cons '7' $ SC.replicate (d - 1) '1'
    where d = div n 2

main :: IO ()
main = SC.putStrLn .
    computeMaxNum . unsafeReadInt =<< LC.getContents