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.
'''
1234
2 2 3 2 3 2 2
33222

'''
n=int(input())
x=int(input())
l={2:0,3:0,5:0,7:0}
while x :
    g=x%10
    if g in l.keys():
        l[g]+=1
    elif g == 4:
        l[2]+=2
        l[3]+=1
    elif g == 6:
        l[3]+=1
        l[5]+=1
    elif g == 8:
        l[7]+=1
        l[2]+=3
    elif g == 9:
        l[2]+=1
        l[3]+=2
        l[7]+=1
    x=x//10
s=''
s+='7'*l[7]
s+='5'*l[5]
s+='3'*l[3]
s+='2'*l[2]
print(s)
				 						 	 	 		 		    	 			