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())
s=input()
l=[]
for i in s:
    i=int(i)
    while i>1:
        l.append(i)
        i-=1
l.sort(reverse=True)

def prime_check(x):
    for i in range(2,x//2+1):
        if x%i==0:
            return False
    return True

def fact(x):
    l=[]
    i = 2
    while True:
        if not prime_check(x):
            if x%i==0:
                x//=i
                l.append(i)
            else:
                i+=1
        else:
            l.append(x)
            break
    return l


f_list=[]
for i in l:
    ch = prime_check(i)
    if ch:
        f_list.append(i)
        i-=1
        while i>1:
            l.remove(i)
            i-=1
    else:
        x = fact(i)
        l.remove(i)
        l.extend(x)
ans = ''
for i in l:
    ans+=str(i)
print(int(ans))
