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())
s = input()

d = {0: {}, 1: {}, 2: {2: 1}, 3: {3: 1}, 4: {2: 2}, 5: {5: 1}, 6: {2: 1, 3: 1}, 7: {7: 1}, 8: {2: 3}, 9: {3: 2}}

t = [0] * 8
for i in s:
    i = int(i)
    if(i > 1):
        for j in range(2, i + 1):
            for k, v in d[j].items():
                t[k] += v

s = ""
for i in range(7, -1, -1):
    if(t[i] > 0):
        n = t[i]
        s += str(i) * n
        for j in range(i, -1, -1):
            for k, v in d[j].items():
                t[k] -= n * v

print(s)

        