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.
l=int(input())
s=input()
a=[]
z=[[],[2],[2,3],[],[2,3,2,2,5],[],[2,3,2,2,5,2,2,2,7]]
for t in range(l):
    n=int(s[t])
    for r in range(1,n+1): 
        i=2
        while i**2<=r:
            while r%i==0:
                a.append(i)
                r//=i
            i+=1
        if r>1:
            a.append(r)
a.sort()
a=a[::-1]
k=[]
for i in range(len(a)):
    if a[i]!=0:
        k.append(a[i])
        for j in range(len(z[a[i]-1])):
            if z[a[i]-1][j]!=0:
                a[a.index(z[a[i]-1][j])]=0
k.sort()
k=k[::-1]
print(*k, sep='')