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
n=int(input())
a=input()
hashmap=defaultdict(int)
for i in a:
    for j in range(2,int(i)+1):
        hashmap[j]+=1
# print(hashmap)
to_delete=[]
for k in hashmap:
    flag=0
    for j in [2,3,5,7]:
        if int(k)%j==0 and k not in [2,3,5,7]:
            if k//j==j:
                hashmap[j]+=hashmap[k]*2
            else:
                hashmap[j] += hashmap[k]
            flag=1
    if flag==1 and k not in [2,3,5,7]:
        to_delete.append(k)
for i in to_delete:
    del hashmap[i]
prime={2:{2:1},3:{3:1,2:1},4:{2:3,3:1},5:{5:1,2:3,3:1},7:{3:2,2:4,5:1}}
keys=sorted(list(hashmap.keys()),reverse=True)
answer=''
# print(hashmap)
for key in keys:
    temp=hashmap[key]
    answer+=str(key)*hashmap[key]
    for j in prime[key]:
        # print(j)
        # print(hashmap[j])
        hashmap[j]-=prime[key][j]*temp

        # print(hashmap)/
print(answer)

