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.
###### Importing Libraries ######
import math
import operator as op
from functools import reduce
from fractions import Fraction as frac
#################################
##### User defined function #####

############ NCR ###############
def ncr(n, r):
    r = min(r, n-r)
    numer = reduce(op.mul, range(n, n-r, -1), 1)
    denom = reduce(op.mul, range(1, r+1), 1)
    return numer / denom
    



############ DSU ###############
global par
# par=[-1 for i in range(100001)]
# t=rd(1)
def find(u):
    if(par[u]<0):
        return u
    else:
        return find(par[u])
def uni(x,y):
    u=find(x)
    v=find(y)
    if u==v:
        return
    if(par[u]<par[v]):
        par[u]+=par[v]
        par[v]=u
    else:    
        par[v]+=par[u]
        par[u]=v
################################        
        
############ READ ###############
def rd(p):
    if(p==0):
        return input()
    if(p==1):
        return int(input())
    if(p==2):
        return map(int,input().split())
    if(p==3):
        return list(map(int,input().split()))
    if(p==4):
        return map(str,input().split())
t=1
for term in range(1,t+1):
    n=int(input())
    s=list(input())
    ans=[]
    for i in range(n):
        if(s[i]=='0'or s[i]=='1'):
            continue
        if(s[i]=='2' or s[i]=='5' or s[i]=='7' or s[i]=='3'):
            ans.append(s[i])
        elif(s[i]=='4'):
            ans=ans+['3','2','2']
        elif(s[i]=='8'):
            ans=ans+['7','2','2']
        elif(s[i]=='9'):
            ans+=['7','3','3','2']
        else:
            ans+=['5','3']
    ans.sort(reverse=True)
    for i in range(len(ans)):
        print(ans[i],end="")
    