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 functools
import heapq as hp
import collections
import bisect
import math


def unpack(func=int):
    return map(func, input().split())


def l_unpack(func=int):
    """list unpack"""
    return list(map(func, input().split()))


def s_unpack(func=int, rev=False):
    """sorted list unpack"""
    return sorted(map(func, input().split()), reverse=rev)


def ml_unpack(n):  # multiple line unpack
    """list of n integers passed on n line, one on each"""
    return [int(input()) for i in range(n)]


def range_n():
    return range(int(input()))


def getint():
    return int(input())


def counter(a):
    d = {}
    for x in a:
        if x in d:
            d[x] += 1
        else:
            d[x] = 1
    return d


def main():
    n = getint()
    a = input()
    ans = []
    for e in a:
        if e in {'0', '1'}:
            continue
        if e == '4':
            ans.append(2)
            ans.append(2)
            ans.append(3)
        elif e == '6':
            ans.append(3)
            ans.append(5)
        elif e == '8':
            ans.append(2)
            ans.append(2)
            ans.append(2)
            ans.append(7)
        elif e == '9':
            ans.append(3)
            ans.append(3)
            ans.append(2)
            ans.append(7)
        else:
            ans.append(int(e))
    ans.sort(reverse=True)
    print(*ans, sep='')


main()
