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.
a = int(input())
l = list(input())
g = []
ans = []
s = []
c2 = 0
c3 = 0
c7 = 0
c5 = 0
for i in l:
    if int(i) != 0 and int(i) != 1:
        s.append(int(i))
for i in s:
    for i in range(2, i + 1):
        if i == 4:
            g.append(2)
            g.append(2)
            c2 += 2
        elif i == 6:
            g.append(2)
            g.append(3)
            c2 += 1
            c3 += 1
        elif i == 8:
            g.append(2)
            g.append(2)
            g.append(2)
            c2 += 3
        elif i == 9:
            g.append(3)
            g.append(3)
            c3 += 2
        else:
            if i == 2:
                c2 += 1
            elif i == 3:
                c3 += 1
            elif i == 7:
                c7 += 1
            elif i == 5:
                c5 += 1
            g.append(i)
dc5 = c7
dc3 = c7 * 2 + c5 - dc5
dc2 = 4 * c7 + 3 * (c5 - dc5) + c3 - dc3
if dc5 <= c5 and dc3 <= c3 and dc2 <= c2:
    for i in range(c7):
        ans.append(7)
    for i in range(c5 - dc5):
        ans.append(5)
    for i in range(c3 - dc3):
        ans.append(3)
    for i in range(c2 - dc2):
        ans.append(2)
    ans.sort()
    ans.reverse()
    print(''.join([str(i) for i in ans]))
else:
    s.sort()
    s.reverse()
    print(''.join([str(i) for i in s]))