Drazil is playing a math game with Varda.

Let's define <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/7020b94c48be2ee5b8eeca05f379c8911bb0e7c4.png" style="max-width: 100.0%;max-height: 100.0%;"/> for positive integer *x* as a product of factorials of its digits. For example, <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/6784d861d9a724d0aeddefcb00b7d0c3442ae586.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

First, they choose a decimal number *a* consisting of *n* digits that contains at least one digit larger than 1. This number may possibly start with leading zeroes. Then they should find maximum positive number *x* satisfying following two conditions:

1. *x* doesn't contain neither digit 0 nor digit 1.

2. <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/7020b94c48be2ee5b8eeca05f379c8911bb0e7c4.png" style="max-width: 100.0%;max-height: 100.0%;"/> = <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/aa57e017a6c74d06b0a54bc47e3f6990e5af38c1.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

Help friends find such number.
The first line contains an integer *n* (1 ≤ *n* ≤ 15) — the number of digits in *a*.

The second line contains *n* digits of *a*. There is at least one digit in *a* that is larger than 1. Number *a* may possibly contain leading zeroes.
from os import path
from sys import stdin, stdout

filename = "../templates/input.txt"
if path.exists(filename):
    stdin = open(filename, 'r')


def input():
    return stdin.readline().rstrip()


def print(*args, sep=' ', end='\n'):
    stdout.write(sep.join(map(str, args)))
    stdout.write(end)


def solution():
    d = {
        '0': '',
        '1': '',
        '2': '2',
        '3': '3',
        '4': '322',
        '5': '5',
        '6': '53',
        '7': '7',
        '8': '7222',
        '9': '7332'
         }
    n = int(input())
    s = input()
    ans = []
    for c in s:
        ans.extend(list(d[c]))
    print(''.join(sorted(ans, reverse=True)))


def main():
    t = 1
    while t:
        solution()
        t -= 1


if __name__ == '__main__':
    main()
