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.
n = int(input())
a = list(map(int,list(input())))

dict1 = {}
for i in range(n):
    for j in range(2,a[i]+1):
        if j in dict1:
            dict1[j]+=1
        else:
            dict1[j] = 1
ans = []
for i in sorted(dict1,reverse = True):
    if i in (2,3,5,7):
        ans += [i for j in range(dict1[i])]
        for j in range(2,i+1):
            dict1[j]-=dict1[i]
    elif i == 4:
        dict1[2]+= dict1[4]*2
    elif i == 6:
        dict1[2]+=dict1[6]
        dict1[3]+=dict1[2]
    elif i == 8:
        dict1[2]+=dict1[8]*3
    elif i == 9:
        dict1[3]+=dict1[9]*2

ans = list(map(str,ans))
print(int(''.join(ans)))