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
for i in l:
    if int(i) != 0 and int(i) != 1:
        s.append(int(i))
for i in s:
    if i == 5 or i == 7:
        ans.append(i)
    else:
        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
                g.append(i)
if c3 <= c2:
    for i in range(c3):
        ans.append(3)
    for i in range(c2 - c3):
        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]))