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
import math
input = sys.stdin.readline

def primefactors(n):
    l = []
    while n % 2 == 0:
        l.append(2)
        n = n // 2

    for i in range(3, int(math.sqrt(n)) + 1, 2):
        while n % i == 0:
            l.append(i)
            n = n // i

    if n > 2:
        l.append(n)

    return l

q = int(input())
n = int(input())
d = {}
s = str(n)
for i in s:
    x = int(i)
    r = 1
    while x > 1:
        r = r*x
        x -= 1

    l = primefactors(r)
    for i in l:
        if i in d:
            d[i] +=1

        else:
            d[i] = 1

ans = []
e = []
# print(d)
for i in d:
    e.append(i)

e.sort(reverse = True)
for i in e:
    v = d[i]
    for j in range(i-1,1,-1):
        h = primefactors(j)
        for k in h:
            d[k] -= v

    while v > 0:
        ans.append(i)
        v -= 1

w = []
for i in ans:
    w.append(str(i))

print("".join(w))