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 bisect import bisect_right, bisect_left
from math import inf, gcd
from collections import defaultdict, Counter
from functools import cache, lru_cache
rvar = lambda: map(int, input().split())
rarr = lambda: list(map(int, input().split()))
rstr = lambda: input().split()
rint = lambda: int(input())

'''Speed up'''
# import sys
# input = sys.stdin.readline


n = rint()
num = input()

mp = {
      '2':'2',
      '3':'3',
      '4':'322',
      '5':'5',
      '6':'53',
      '7':'7',
      '8':'7222',
      '9':'7332'
      }

res = [mp[v] for v in num if v not in ('0', '1')]
res = "".join(res)
res = sorted(res)
res = "".join(res[::-1])
print(res)