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.
# Created by iN_siDious.
# Copyright © 2023 iN_siDious. All rights reserved.
import sys
import random
from math import *
from string import ascii_lowercase
from collections import Counter, defaultdict, deque
from itertools import accumulate, combinations, permutations
from heapq import heappushpop, heapify, heappop, heappush
from bisect import bisect_left,bisect_right
from types import GeneratorType
def bootstrap(f, stack=[]):
    def wrappedfunc(*args, **kwargs):
        if stack:
            return f(*args, **kwargs)
        else:
            to = f(*args, **kwargs)
            while True:
                if type(to) is GeneratorType:
                    stack.append(to)
                    to = next(to)
                else:
                    stack.pop()
                    if not stack:
                        break
                    to = stack[-1].send(to)
            return to
    return wrappedfunc
inp = lambda: sys.stdin.buffer.readline().decode().strip()
out=sys.stdout.write
def S():
    return inp()
def I():
    return int(inp())
def MI():
    return map(int, inp().split())
def MS():
    return inp().split()
def LS():
    return list(inp().split())
def LI():
    return list(map(int,inp().split()))
def print1(x):
    return out(str(x)+"\n")
def print2(x,y):
    return out(str(x)+" "+str(y)+"\n")
def print3(x,y,z):
    return out(str(x)+" "+str(y)+" "+str(z)+"\n")
def Query(i,j):
    print3('?', i, j)
    sys.stdout.flush()
    qi=int(inp())
    return qi
def print_arr(arr):
    for num in arr:
        out(str(num)+" ")
    out(str("\n"))
n=I()
s=[c for c in S()]
s.sort(reverse=True)
cnt=Counter()
ans=""
for c in s:
    if c=="9":
        cnt["3"]+=2
        cnt["7"]+=1
    elif c=="8":
        cnt["2"]+=3
        cnt["7"]+=1
    elif c=="6":
        cnt["3"]+=1
        cnt["5"]+=1
    elif c=="4":
        cnt["2"]+=2
        cnt["3"]+=1
    elif c>="2": cnt[c]+=1
for c in sorted(cnt,reverse=True): 
    for _ in range(cnt[c]):
        ans+=c
print1(ans)