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 math import sqrt, ceil


def main():
    nDigits = input()
    number = input().replace('0', '').replace('1', '')
    return maximumValueBuiltFrom(number)


def maximumValueBuiltFrom(number):
    digitsFrom = {'2': ('2',), '3': ('3',), '4': ('3', '2', '2'),
                  '5': ('5', ), '6': ('5', '3'), '7': ('7', ),
                  '8': ('7', '2', '2', '2'), '9': ('7', '3', '3', '2')}
    newDigits = []
    for oldDigit in number:
        newDigits.extend(digitsFrom[oldDigit])

    newDigits.sort(reverse=True)
    return ''.join(newDigits)


if __name__ == '__main__':
    print(main())
    # main()
