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 sys
input = sys.stdin.readline
import math
 
def inpit(): #int
    return(int(input()))
def inplt(): #list 
    return(list(map(int,input().split())))
def inpstr(): #string
    s = input()
    return(list(s[:len(s) - 1]))
def inpspit(): #spaced intergers 
    return(map(int,input().split()))
n = inpit()
s = inpstr()

d = {1:[],
     2:[2],
     3:[3],
     4:[3,2],
     5:[5],
     6:[3,2,5,3,2,2,2],
     7:[7] ,
     8:[2,2,2,7,3,2,5,2,2,3,2],
     9:[2,2,2,7,3,2,5,2,2,3,2]}
a =[] 
for i in s:
    if(i !='1' or i!= '0'):
        a = a + d[int(i)]
        
import math

print(''.join(map(str,sorted(a,reverse = True))))