#include <bits/stdc++.h>
using namespace std;
int n, len = 0;
char num[20], res[100];
bool ok = false;
char cmp(char a, char b) { return a > b; }
int main() {
  cin >> n;
  cin.get();
  cin.get(num, 20, '\n');
  for (int i = 0; i < n; i++) {
    switch (num[i]) {
      case '0':
      case '1':
        ok = true;
        break;
      case '2':
        res[len++] = '2';
        break;
      case '3':
        res[len++] = '3';
        break;
      case '4':
        for (int j = 0; j < 2; j++) res[len++] = '2';
        res[len++] = '3';
        break;
      case '5':
        res[len++] = '5';
        break;
      case '6':
        res[len++] = '3';
        res[len++] = '5';
        break;
      case '7':
        res[len++] = '7';
        break;
      case '8':
        for (int j = 0; j < 3; j++) res[len++] = '2';
        res[len++] = '7';
        break;
      case '9':
        for (int j = 0; j < 2; j++) res[len++] = '3';
        res[len++] = '2';
        res[len++] = '7';
        break;
    }
  }
  res[len] = '\0';
  sort(res, res + len, cmp);
  cout << (len >= n ? res : (ok ? res : num));
  return 0;
}

### Prompt

Please formulate a CPP solution to the following problem:

Drazil is playing a math game with Varda.

Let's define <image> for positive integer x as a product of factorials of its digits. For example, <image>.

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. <image> = <image>.

Help friends find such number.

Input

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.

Output

Output a maximum possible integer satisfying the conditions above. There should be no zeroes and ones in this number decimal representation.

Examples

Input

4
1234


Output

33222


Input

3
555


Output

555

Note

In the first case, <image>

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int n, len = 0;
char num[20], res[100];
bool ok = false;
char cmp(char a, char b) { return a > b; }
int main() {
  cin >> n;
  cin.get();
  cin.get(num, 20, '\n');
  for (int i = 0; i < n; i++) {
    switch (num[i]) {
      case '0':
      case '1':
        ok = true;
        break;
      case '2':
        res[len++] = '2';
        break;
      case '3':
        res[len++] = '3';
        break;
      case '4':
        for (int j = 0; j < 2; j++) res[len++] = '2';
        res[len++] = '3';
        break;
      case '5':
        res[len++] = '5';
        break;
      case '6':
        res[len++] = '3';
        res[len++] = '5';
        break;
      case '7':
        res[len++] = '7';
        break;
      case '8':
        for (int j = 0; j < 3; j++) res[len++] = '2';
        res[len++] = '7';
        break;
      case '9':
        for (int j = 0; j < 2; j++) res[len++] = '3';
        res[len++] = '2';
        res[len++] = '7';
        break;
    }
  }
  res[len] = '\0';
  sort(res, res + len, cmp);
  cout << (len >= n ? res : (ok ? res : num));
  return 0;
}

```