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 math
#n,m=map(int,input().split())
from collections import Counter
#for i in range(n):
import math
#for _ in range(int(input())):
#n = int(input())
#for _ in range(int(input())):
#n = int(input())
import bisect
'''for _ in range(int(input())):

    n=int(input())

    n,k=map(int, input().split())

    arr = list(map(int, input().split()))'''
#n, m, k = [int(x) for x in input().split()]
#n,m=map(int,input().split())
n=int(input())
s=list(input())
#s.sort(reverse=True)
d={}
d[2]=2
d[3]=3
d[4]=322
d[5]=5
d[6]=53
d[7]=7
d[8]=7222
d[9]=7332
ans=""
for i in s:
    if i!="0" and i!="1":
        ans+=str(d[int(i)])
ans=list(ans)
print("".join(sorted(ans))[::-1])


