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.
def a(ans, n, pf):
    if n == 1:
        return ans
    for i in pf:
        if n % i == 0:
            m = a(ans + [i], n // i, pf[:i+1])
            if m != None:
                return m
        else:
            return None
    return None            
n = int(input())
s = input()
pf1 = [1, 2, 6, 24, 120, 720, 5040, 40320, 362880]
pf = [2, 6, 120, 5040]
pfo = {2:2, 6:3, 120:5, 5040:7}
summ = 1
for i in s:
    if int(i) != 0:
        summ *= pf1[int(i)-1]
for i in pf:
    if summ % i == 0:
        m = a([i], summ // i, pf[:i+1])
        if m != None:
            break
    else:
        break
m.sort(reverse = True)
for i in m:
    print(pfo[i], end = '')