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 convert(digit_string):
    prime_replacement = {2: [2], 3: [3], 4: [2, 2, 3], 5: [5], 6: [3, 5],
                         7: [7], 8: [2, 2, 2, 7], 9: [2, 3, 3, 7]}
    converted_digits = []
    for dig in digit_string:
        if int(dig) not in (0, 1):
            converted_digits.extend(prime_replacement[int(dig)])
    return converted_digits


input_file = sys.stdin.read(-1).replace("\r\n", "\r")
input_file = input_file.split()

num_digits = int(input_file[0])
digits = input_file[1]

new_digits = convert(digits)
new_digits.sort(reverse=True)

num = ""
for new_digit in new_digits:
    num += str(new_digit)
print(num)
