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.
def fact(arr):
    arr2=[]
    arr3 = []
    arr4 = []
    for valor in arr:
        if valor==2:
            arr2.append(2)
        elif valor==3:
            arr2.append(3)
        elif valor==4:
            arr2.append(2)
            arr2.append(2)
            arr2.append(3)
        elif valor==5:
            arr2.append(5)
        elif valor==6:
            arr2.append(3)
            arr2.append(5)
        elif valor==7:
            arr2.append(7)
        elif valor==8:
            arr2.append(2)
            arr2.append(2)
            arr2.append(2)
            arr2.append(7)
        elif valor==9:
            arr2.append(3)
            arr2.append(3)
            arr2.append(2)
            arr2.append(7)
        else:
            continue
    arr2.sort(reverse=True)
    arr3=map(str, arr2)
    arr4=''.join(arr3)
    return arr4

n = int(input())
val = int(input())
arr=map(int,str(val))
print(fact(arr))