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.
from sys import stdin,stdout
input = stdin.readline
from math import sqrt,gcd,ceil,inf,log2
# from collections import Counter,deque
# from heapq import heapify,heappop,heappush
# from time import time
# from bisect import bisect, bisect_left,insort


o = int(input())
n = input().rstrip('\n')
A = {}
for i in n:
    for j in range(2,int(i) + 1):
        if j == 8:
            A[2] += 3
        elif j == 9:
            A[3] += 2
        elif j == 6:
            A[2] += 1
            A[3] += 1
        elif j == 4:
            A[2] += 2
        else:
            if j in A:
                A[j] += 1
            else:
                A[j] = 1
count = 0
ans  = ""   
# print(A)         
for j in range(9,1,-1):
    if (j in A):
        for i in range(A[j] - count):
            ans += str(j)
            if j ==7:
                A[3] -= 1
                A[2] -= 3
            if j == 5:
                A[2] -= 2              
        count = A[j]   
print(ans)         

