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.
n=int(input())
a=int(input())
sa=str(a)
numberl=[]
ans=""
for i in range(n):
    if sa[i] == '0' or sa[i] == '1':
        continue
    elif sa[i] == '2':
        numberl.append(2)
    elif sa[i] == '3':
        numberl.append(3)
        numberl.append(2)
    elif sa[i] == '4':
        numberl.append(3)
        numberl.append(2)
        numberl.append(2)
        numberl.append(2)
    elif sa[i] == '5':
        numberl.append(5)
    elif sa[i] == '6':
        numberl.append(3)
        numberl.append(2)
        numberl.append(5)
    elif sa[i] == '7':
        numberl.append(7)
    elif sa[i] == '8':
        numberl.append(7)
        numberl.append(2)
        numberl.append(2)
        numberl.append(2)
    elif sa[i] == '9':
        numberl.append(3)
        numberl.append(3)
        numberl.append(2)
        numberl.append(2)
        numberl.append(2)
        numberl.append(7)
c2=numberl.count(2)
c3=numberl.count(3)
c5=numberl.count(5)
c7=numberl.count(7)
ans+="7"*c7
ans+="5"*c5
ans+="3"*c3
ans+="2"*(c2-c3)
ans1=list(ans)
ans2=sorted(ans1,reverse= True)
#print(ans2)
res = ""
for i in ans2:
    res+=i
print(int(res))