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, Counter
from bisect import bisect, bisect_left
from math import sqrt, gcd, ceil, factorial


# file = open("input.txt", "r")

MOD = 10**9 + 7
inf = float("inf")
ans_ = []
def read(): return list(map(int, input().strip().split()))
# def read(f):return list(map(int, f.readline().strip().split()))

def f(x):
    a = []
    i = 2
    while x > i:
        while x%i == 0:x//=i;a.append(i)
        i += 1
    if x > 1:a.append(x)
    return(a)

# for _ in range(int(input())):
n = int(input()); x = input().strip()
d  = defaultdict(int)
a = []
dic = {4:[3,2,2], 6:[5,2], 8:[7,2,2,2], 9:[7,3,3,3]}
for i in x:
    i = int(i)
    if i == 1:continue
    elif i in dic:a.extend(dic[i])
    else:a.append(i)
a.sort(reverse=True)
ans_.append(("").join(map(str,a)))
    

for i in ans_:
    print(i)