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 sys


def uno(): return int(sys.stdin.readline().strip())


def dos(): return sys.stdin.readline().strip()


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


def cuatro(): return sys.stdin.readline().strip().split()


def pmod(b, x, m):
    res = 1
    while x:
        if x & 1:
            res = (res*b) % m
        x >>= 1
        b = (b*b) % m
    return res


def inv(a, m):
    return pmod(a, m-2, m)


def prn(s):
    ans = ""
    for i in s:
        ans += i
    print(ans)


n = uno()
a = dos()
ans = ""
for i in a:
    if i == '4':
        ans += "322"
    elif i == 6:
        ans += "35"
    elif i == '8':
        ans += '2227'
    elif ans == "9":
        ans += "9927"
    elif i != '0' and i != '1':
        ans += i
ans = sorted(ans, reverse=True)
prn(ans)
