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 collections import defaultdict


mappings = {
    4: [2,2],
    6: [2,3],
    8: [2,2,2],
    9: [3,3]
}

def main():
    N = int(input())
    s = [int(i) for i in input()]

    cnt = defaultdict(int)
    for i in s:
        if i <= 1: continue
        for k in range(i,1,-1):
            cnt[k] += 1
    
    prev = 0
    res = []

    for i in range(9,0,-1):
        if i not in cnt: continue
        cnt[i] -= prev
        if (cnt[i] > 0):
            if i in mappings:
                for num in mappings[i]: cnt[num] += cnt[i]
            else:
                res.extend([i] * cnt[i])
                prev += cnt[i]
    print(*res, sep="")

main()
        
    

