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.
#include <bits/stdc++.h>
using namespace std;

bool is[10];

int main() {
    ios_base::sync_with_stdio(0);
    
    int n;
    cin >> n;
    string S;
    cin >> S;
    double f[15];
    f[0] = 1;
    for(int i = 1; i <= 9; i++)
        f[i] = f[i-1] * i;
    
    string RES = "";
    
    is[1] = is[3] = is[5] = is[7] = 1;
    for(int i = 0; i < S.size(); i++) {
        
        int X = S[i] - '0';
        
        while(is[X] == 0) {
            int x = X;
            for(int j = 2; j <= X && x > 1; j++) {
                while(x%j == 0) {
                    RES += j + '0';
                    x /= j;
                }
            }
            X--;
        }
        
        if(X > 1) {
            RES += X + '0';
        }
        
        
    }
    sort(RES.begin(),RES.end(),greater<char>());
    cout << RES << endl;
    
    
}