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.
len=int(input(""))
n=input("")
i=0
a=0
b=0
c=0
d=0
while i<len :
    if n[i]=='2' :
        a+=1
    elif n[i]=='3' :
        b+=1
    elif n[i]=='4' :
        a+=2
        b+=1
    elif n[i]=='5' :
        c+=1
    elif n[i]=='6' :
        a+=1
        b+=1
        c+=1
    elif n[i]=='7' :
        d+=1
    elif n[i]=='8' :
        a+=3
        d+=1
    elif n[i]=='9' :
        a+=3
        b+=2
        d+=1
    i+=1
string=""
e=d+a+b+c
j=0
while j<e :
    if j<d :
        string+='7'
    elif d<=j<(d+c) :
        string+='5'
    elif (d+c)<=j<(d+c+b) :
        string+='3'
    elif (d+c+b)<=j<e :
        string+='2'
    j+=1
print(string)
