
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE RankNTypes #-}

import Data.Array (Array, array, (!))
import Data.Array.ST (STArray, MArray, runSTArray, readArray, writeArray, newArray)
import Data.Maybe (fromJust, catMaybes)

import Control.Monad (forM_, when)
import Control.Monad.ST (ST)

newtype NumStr = NumStr {getString :: String} deriving Eq
instance Ord NumStr where
  compare (NumStr s1) (NumStr s2)
    | l1 < l2 = LT
    | l1 > l2 = GT
    | otherwise = case compare (head s1) (head s2) of
                    EQ -> compare (NumStr (tail s1)) (NumStr (tail s2))
                    n -> n
    where
      l1 = length s1
      l2 = length s2

match :: Array Char Int
match = array ('1','9') [('1',2),('2',5),('3',5),('4',4),('5',5),('6',6),('7',3),('8',7),('9',6)]

main :: IO ()
main = do
  n <- read . head . words <$> getLine
  as <- map head . words <$> getLine
  let solv = do
      arr <- initialize n
      forM_ [2..n] $ \i -> dp i as arr
      return arr
  let dptable = runSTArray solv
  putStrLn $ fromJust $ dptable ! n

initialize :: Int -> (forall s. ST s (STArray s Int (Maybe String)))
initialize n = do
  arr <- newArray (0,n) Nothing
  writeArray arr 0 (Just "")
  return arr

dp :: Int -> [Char] -> STArray s Int (Maybe String) -> ST s ()
dp n as arr = do
  ds <- catMaybes <$> sequence [fmap (a:) <$> readArray arr (n - m) | a <- as, let m = match!a, n-m>=0]
  when (not $ null ds) $ 
    writeArray arr n $ Just $ getString $ maximum $ fmap NumStr $ ds
