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()) ; ans=[] ; a=input()  ; num=[]
for i in a:num.append(int(i)) 
for i in range(n):
    if num[i]%2==1 and num[i]!=1:
        ans.append(num[i])
    else:
        if num[i]==2:
            ans.append(2)
        elif num[i]==6:
            ans.append(5)
            ans.append(3)
            ans.append(2)
        elif num[i]==4:
            ans.append(3)
            ans.append(2)
            ans.append(2)
        elif num[i]==8:
            ans.append(7)
            ans.append(2)
            ans.append(2)
            ans.append(2)
ans.sort(reverse=True)
for i in ans:
    print(i,end="")