x = int(input())
n = input()
factorial = {
2:[2],
3:[3],
4:[3,2,2],
5:[5],
6:[3,5],
7:[7],
8:[7,2,2,2],
9:[7,3,3,2]
}
res = []
for i in n:
num = int(i)
if num != 1 and num != 0:
res += factorial[num]
res = sorted(res,reverse = True)
s = ""
for i in res:
s+=str(i)
print(int(s))
/* ____ _ __ _ _ _
| _ \ _ __ ___ _ __ ___ | |/ /__ _ _ __ ___ __ _| | | | __ _(_)_ __
| |_) | '__/ _ \ '_ ` _ \ | ' // _` | '_ ` _ \ / _` | | _ | |/ _` | | '_ \
| __/| | | __/ | | | | | | . \ (_| | | | | | | (_| | | | |_| | (_| | | | | |
|_| |_| \___|_| |_| |_| |_|\_\__,_|_| |_| |_|\__,_|_| \___/ \__,_|_|_| |_|
*/
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;
typedef long double lld;
#define hell 1000000007
#define PI 3.141592653589793238462
#define INF 1e18
#define vi vector<ll>
#define pb push_back
#define ppb pop_back
#define mii map<ll,ll>
#define pii pair<ll,ll>
#define mp make_pair
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
/*____________________________________________________________________________________________________________________________________________________________________________________________________*/
vector<ll> sieve(int n) {int*arr = new int[n + 1](); vector<ll> vect; for (int i = 2; i <= n; i++)if (arr[i] == 0) {vect.push_back(i); for (int j = 2 * i; j <= n; j += i)arr[j] = 1;} return vect;}
ll mod_add(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a + b) % m) + m) % m;}
ll mod_mul(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a * b) % m) + m) % m;}
ll mod_sub(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a - b) % m) + m) % m;}
ll expo(ll a, ll b, ll mod) {ll res = 1; while (b > 0) {if (b & 1)res = (res * a) % mod; a = (a * a) % mod; b = b >> 1;} return res;}
/*____________________________________________________________________________________________________________________________________________________________________________________________________*/
void solve()
{
ll n;
cin>>n;
ll a;
cin>>a;
mii ma;
while(a!=0){
ll x=a%10;
a/=10;
if(x==0 || x==1){
continue;
}
else if(x==2 || x==3 || x==5 || x==7){
ma[x]++;
}
else if(x==9){
ma[7]++;
ma[3]+=2;
ma[2]++;
}
else if(x==8){
ma[7]++;
ma[2]+=3;
}
else if(x==6){
ma[5]++;
ma[3]++;
}
else if(x==4){
ma[3]++;
ma[2]+=2;
}
}
if(ma[7]!=0){
for(ll i=0;i<ma[7];i++){
cout<<'7';
}
}
if(ma[5]!=0){
for(ll i=0;i<ma[5];i++){
cout<<'5';
}
}
if(ma[3]!=0){
for(ll i=0;i<ma[3];i++){
cout<<'3';
}
}
if(ma[2]!=0){
for(ll i=0;i<ma[2];i++){
cout<<'2';
}
}
cout<<endl;
return;
}
int main()
{
ios_base::sync_with_stdio(false);
int t=1;
// cin>>t;
for(ll i=0;i<t;i++){
solve();
}
return 0;
}
4A - Watermelon | 476A - Dreamoon and Stairs |
1409A - Yet Another Two Integers Problem | 977A - Wrong Subtraction |
263A - Beautiful Matrix | 180C - Letter |
151A - Soft Drinking | 1352A - Sum of Round Numbers |
281A - Word Capitalization | 1646A - Square Counting |
266A - Stones on the Table | 61A - Ultra-Fast Mathematician |
148A - Insomnia cure | 1650A - Deletions of Two Adjacent Letters |
1512A - Spy Detected | 282A - Bit++ |
69A - Young Physicist | 1651A - Playoff |
734A - Anton and Danik | 1300B - Assigning to Classes |
1647A - Madoka and Math Dad | 710A - King Moves |
1131A - Sea Battle | 118A - String Task |
236A - Boy or Girl | 271A - Beautiful Year |
520B - Two Buttons | 231A - Team |
479C - Exams | 1030A - In Search of an Easy Problem |