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.

one = [1]
two = [2]
#three = [2,3]
three = [3]
#four = [2,2,2,3]
four = [2,2,3]
#five = [2,2,2,3,5]
five = [5]
#six = [2,2,2,2,3,3,5]
six = [2,3,5]
#seven = [2,2,2,2,3,3,5,7]
seven = [7]
#eight = [2,2,2,2,2,2,2,3,3,5,7]
eight = [2,2,2,7]
#nine = [2,2,2,2,2,2,2,3,3,3,3,5,7]
nine = [2,2,2,3,3,7]

n = int(input())
a = int(input())

digit_string = str(a)
digit_map = map(int, digit_string)
a_list = list(digit_map)

#print(a_list)

ans = []
for i in range(len(a_list)):
    if a_list[i] == 2:
        ans = ans + two
    elif a_list[i] == 3:
        ans = ans + three
    elif a_list[i] == 4:
        ans = ans + four
    elif a_list[i] == 5:
        ans = ans + five
    elif a_list[i] == 6:
        ans = ans + six
    elif a_list[i] == 7:
        ans = ans + seven
    elif a_list[i] == 8:
        ans = ans + eight
    elif a_list[i] == 9:
        ans = ans + nine

ans.sort(reverse=True)
#print(ans)

strings = [str(integer) for integer in ans]
a_string = "".join(strings)
an_integer = int(a_string)

print(an_integer)
