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 as dd
d=dd(lambda:0)
from sys import stdin
stdin.readline

def mp():return map(int,input().split())
def it():return int(input())

n=it()
s=list(input())
for i in range(n):
	if s[i]=='1' or s[i]=='0':
		continue
	elif (int(s[i])!=9 and int(s[i])%2!=0) or s[i]=='0' or s[i]=='2':
		# d.append(int(s[i]))
		d[int(s[i])]+=1
	elif s[i]=='9':
		d[7]+=1
		d[3]+=2
		d[2]+=1
	elif s[i]=='4':
		d[2]+=2
		d[3]+=1
	elif s[i]=='6':
		d[5]+=1
		d[3]+=1
	elif s[i]=='8':
		d[2]+=3
		d[7]+=1
v=[]
j=[]
# print(dict(d))
for i in d:
	j.append([i,d[i]])
j.sort()
j.reverse()
for t in range(len(j)):
	v.append(str(j[t][0])*j[t][1])
k=''.join(v)
print(k)
