#include <bits/stdc++.h>
using namespace std;
namespace Solve {
const int MAXN = 20;
char s[MAXN];
int n, ans[MAXN], cnt[MAXN];
void work() {
  scanf("%d", &n);
  getchar();
  scanf("%s", s);
  for (int i = 0; s[i]; i++) {
    switch (s[i]) {
      case '0':
        ans[i] = -1;
        break;
      case '1':
        ans[i] = -1;
        break;
      case '2':
        ans[i] = 2;
        break;
      case '3':
        ans[i] = 3;
        break;
      case '4':
        ans[i] = 322;
        break;
      case '5':
        ans[i] = 5;
        break;
      case '6':
        ans[i] = 53;
        break;
      case '7':
        ans[i] = 7;
        break;
      case '8':
        ans[i] = 7222;
        break;
      case '9':
        ans[i] = 7332;
        break;
      default:
        break;
    }
  }
  memset(cnt, 0, sizeof(cnt));
  for (int i = 0; i < n; i++) {
    if (ans[i] == -1) continue;
    while (ans[i]) {
      cnt[ans[i] % 10]++;
      ans[i] /= 10;
    }
  }
  for (int i = 9; i >= 2; i--)
    while (cnt[i]) printf("%d", i), cnt[i]--;
  printf("\n");
  return;
}
}  // namespace Solve
int main() {
  Solve::work();
  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;
namespace Solve {
const int MAXN = 20;
char s[MAXN];
int n, ans[MAXN], cnt[MAXN];
void work() {
  scanf("%d", &n);
  getchar();
  scanf("%s", s);
  for (int i = 0; s[i]; i++) {
    switch (s[i]) {
      case '0':
        ans[i] = -1;
        break;
      case '1':
        ans[i] = -1;
        break;
      case '2':
        ans[i] = 2;
        break;
      case '3':
        ans[i] = 3;
        break;
      case '4':
        ans[i] = 322;
        break;
      case '5':
        ans[i] = 5;
        break;
      case '6':
        ans[i] = 53;
        break;
      case '7':
        ans[i] = 7;
        break;
      case '8':
        ans[i] = 7222;
        break;
      case '9':
        ans[i] = 7332;
        break;
      default:
        break;
    }
  }
  memset(cnt, 0, sizeof(cnt));
  for (int i = 0; i < n; i++) {
    if (ans[i] == -1) continue;
    while (ans[i]) {
      cnt[ans[i] % 10]++;
      ans[i] /= 10;
    }
  }
  for (int i = 9; i >= 2; i--)
    while (cnt[i]) printf("%d", i), cnt[i]--;
  printf("\n");
  return;
}
}  // namespace Solve
int main() {
  Solve::work();
  return 0;
}

```