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.
w = int(input())
s = input()
F = [1] * 18
for i in range(1, 18):
    F[i] = i * F[i - 1]
a = 0
b = 0
c = 0
d = 0
for i in range(w):
    z = int(s[i])
    if z > 8:
        b += 2
    if z > 7:
        a += 3
    if z > 6:
        d += 1
    if z > 5:
        a += 1
        b += 1
    if z > 4:
        c += 1
    if z > 3:
        a += 2
    if z > 2:
        b += 1
    if z > 1:
        a += 1
ans = ''
a -= d * 4
b -= d * 2
c -= d
ans += '7' * d
b -= c
a -= c * 3
ans += '5' * c
a -= b
ans += '3' * b
ans += '2' * a
print(ans)

    
    
