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.
# cook your dish here
def counter(n):
    if n == 2:
        arr[n] += 1
    elif n == 3:
        arr[n] += 1
    elif n == 4:
        arr[2] += 2
    elif n == 5:
        arr[5] += 1
    elif n == 6:
        arr[2] += 1
        arr[3] += 1
    elif n == 7:
        arr[7] += 1
    elif n == 8:
        arr[2] += 3
    elif n == 9:
        arr[3] += 2


def reducer(n):
    if n == 7:
        arr[2] -= 4
        arr[3] -= 2
        arr[5] -= 1
    elif n == 5:
        arr[2] -= 3
        arr[3] -= 1
    elif n == 3:
        arr[2] -= 1


arr = [0] * 10
t = int(input())
f = input()
for i in f:
    for j in range(int(i) + 1):
        counter(int(j))
st = ''
for i in reversed(range(10)):
    while arr[i]:
        st = st + str(i)
        reducer(i)
        arr[i] -= 1
print(st)
