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 collections import defaultdict,Counter
import math
import bisect
from itertools import accumulate
from math import ceil, log,gcd
from functools import lru_cache 
from sys import stdin, stdout
def read():
    return stdin.readline().rstrip()
import sys
import heapq

# total = int(input())
# _,n =  ([int(p) for p in read().split()])

# ss= read()
k = ([int(p) for p in read().split()])
x = ([int(p) for p in read().split()])

x  = list(str(x))

y = [0] * 10
for i in x:
    i = int(i)
    if i == 2:
        y[2]+=1
    elif i == 3:
        y[3] +=1
    elif i == 4:
        y[2] += 2
        y[3] += 1
    elif i==5:
        y[5] +=1        
    elif i == 6:
        y[5] += 1
        y[3] += 1
    elif i == 7:
        y[7] += 1
    elif i == 8:
        y[7] += 1
        y[2] += 3
        
    elif i == 9:
        y[7] += 1
        y[2] += 1
        y[3] += 2
        
        
s = []

for i in range(9,1,-1):
    s+=[i] * y[i]
        
print(''.join(map(str,s)))    
        