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.
n = int(input())
a = input()
dict = {}
splits = {8 : [(2, 3), (7, 1)], 9 : [(3, 2), (2, 1), (7, 1)], 
        6 : [(3, 1), (5, 1)], 4 : [(2, 2), (3, 1)]}
product = 1
for i in a :
    digit = int(i)
    if digit <= 1 :
        continue
    if digit in splits :
        for l in splits[digit] :
            num = l[0]
            times = l[1]
            if num not in dict :
                dict[num] = 0
            dict[num] += times
    else :
        if digit not in dict :
            dict[digit] = 0
        dict[digit] += 1
print("".join(str(i) * dict[i] for i in sorted(dict.keys(), reverse = True)))