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.
numbers = {9:0, 8:0, 7:0, 6:0, 5:0, 4:0, 3:0, 2:0,}
res = {9:0, 8:0, 7:0, 6:0, 5:0, 4:0, 3:0, 2:0,}
n = int(input())
ar = int(input())
for i in range(n):
    x = ar % 10
    ar = int(ar / 10)
    if x != 0 and x != 1: numbers.update({x: numbers[x] + 1})
for key in numbers:
    if numbers[key] > 0:
        if key == 9:
            for i in range(numbers[key]):
                res.update({key: res[key] + 1})
        if key == 8:
            res.update({
                2: res[2] + numbers[2],
                3: res[3] + numbers[3],
                7: res[7] + numbers[7],
                }
            )
        if key == 5 or key == 7:
            res.update({
                key: res[key] + numbers[key]
                }
            )
        if key == 6:
            res.update({
                2: res[2] + numbers[2],
                3: res[3] + numbers[3],
                5: res[5] + numbers[5],
                }
            )
        if key == 4:
            res.update({
                2: res[2] + 2,
                3: res[3] + numbers[3],
                }
            )
        if key == 3 or key == 2:
            res.update({
                key: res[key] + numbers[key]
                }
            )
x = []
for i in res:
    for j in range(res[i]):
        x.append(str(i))
print("".join(x))