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.
fact={
    2:0,
    3:0,
    5:0,
    7:0
}

pollin_2=lambda x:x//2+x//4+x//8
pollin_3=lambda x:x//3+x//9
pollin_5=lambda x:x//5
pollin_7=lambda x:x//7

n=int(input())
s=input()

for i in s:
 fact[2]+=pollin_2(int(i))
 fact[3]+=pollin_3(int(i))
 fact[5]+=pollin_5(int(i))
 fact[7]+=pollin_7(int(i))

print('7'*fact[7],end='')
fact[7]=0
fact[5]-=fact[7]
fact[3]-=2*fact[7]
fact[2]-=4*fact[7]

print('5'*fact[5],end='')
fact[5]=0
fact[3]-=fact[5]
fact[2]-=3*fact[5]

print('3'*fact[3],end='')
fact[3]=0
fact[2]-=fact[3]

print('2'*fact[2])