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.
import string
NUMBERS=[]

def factor(x):
    if x == 2 or x==5 or x== 7:
        NUMBERS.append(x)
        return
    else:
       xx = x 
       while x!= 1:
           for i in range(2,4):
               if x%i==0:
                   x = x/i
                   NUMBERS.append(i)
       factor(xx-1)
    return
    


n = int(input())

input_value = input()
num = []
j = 0
for i in range(n):  
    if input_value[i] != '1' and input_value[i] != '0':
        num.append(int(input_value[i]))
        j = j+1
for x in num:
    factor (x)
for x in NUMBERS:
    if x==3:
        NUMBERS.remove(2)

NUMBERS.sort(reverse=True )

print("".join( map(str, NUMBERS)))


        
        
    
