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.
import math
import sys


def In():
    return map(int, sys.stdin.readline().split())


def drazilandfra():
    def recur(num):
        if num == 2 or num ==3 or num == 5 or num == 7:
            return [num]
        nowans = []
        for i in range(num, 1, -1):
            factor = []
            for x in range(2, int(math.sqrt(i))+1):
                if not i % x:
                    factor += [x, i // x]
            if not factor:
                nowans.append(i)
                continue
            for x in factor:
                nowans += recur(x)
        return nowans

    n = int(input())
    ans = []
    for i in input().rstrip().strip('0'):
        if i != '1':
            ans += recur(int(i))
    print(*sorted(ans, reverse=True),sep='')


drazilandfra()
