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


def fill_prime(x):

    is_prime = [True] * x
    is_prime[0] = is_prime[1] = False
    for i in range(2, x):
        if is_prime[i]:
            for j in range(i * i, x, i):
                is_prime[j] = False
    primes = set()
    for i in range(2, x):
        if is_prime[i]:
            primes.add(i)
    return primes


def fill_factorial(x):

    fac = [0 for _ in range(x)]
    fac[0] = fac[1] = 1
    for i in range(2, x):
        fac[i] = i * fac[i - 1]

    return fac


def factorize(x):
    factors = {}
    k = int(math.sqrt(x)) + 1
    for i in range(2, k):
        if x == 1 or x in primes:
            break
        if x % i == 0 and i not in factors:
            factors[i] = 0
        while x % i == 0:
            x //= i
            factors[i] += 1
    if x != 1:
        factors[x] = 1
    return factors


def ffactor(x, fac, primes):

    if x in primes:
        return [x]

    ret = []
    rem = fac[x]

    while x >= 2:

        x -= 1

        if x in primes:
            rem //= fac[x]
            ret.append(x)
            break

    factors = factorize(rem)

    for p in sorted(factors,  reverse=True):
        for e in range(factors[p]):
            ret.append(p)
        if p != 2:
            factors[p - 1] -= factors[p]

    return ret


MAX = 10

fac = fill_factorial(MAX)
primes = fill_prime(MAX)

super_fact = [ffactor(i, fac, primes) for i in range(MAX)]

n = int(input())
a = input()
ret = ''
for num in a:
    for x in super_fact[int(num)]:
        ret += str(x)
print(''.join(sorted(ret, reverse=True)))
