#include <bits/stdc++.h>
using namespace std;
long long fact(int n) {
  long long ans = 1;
  for (int i = 1; i <= n; i++) ans *= i;
  return ans;
}
int main() {
  int N;
  cin >> N;
  string str;
  cin >> str;
  int freq[10] = {0};
  for (int i = 0; i < N; i++) {
    int val = fact(str[i] - '0');
    for (int p = 2; p < 8; p++) {
      while (val % p == 0) {
        freq[p]++;
        val /= p;
      }
    }
  }
  for (int i = 7; i >= 2; i--) {
    while (freq[i] != 0) {
      cout << i;
      int val = fact(i);
      for (int p = 2; p < 8; p++) {
        while (val % p == 0) {
          freq[p]--;
          val /= p;
        }
      }
    }
  }
  cout << endl;
  return 0;
}

### Prompt

In Cpp, your task is to solve 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;
long long fact(int n) {
  long long ans = 1;
  for (int i = 1; i <= n; i++) ans *= i;
  return ans;
}
int main() {
  int N;
  cin >> N;
  string str;
  cin >> str;
  int freq[10] = {0};
  for (int i = 0; i < N; i++) {
    int val = fact(str[i] - '0');
    for (int p = 2; p < 8; p++) {
      while (val % p == 0) {
        freq[p]++;
        val /= p;
      }
    }
  }
  for (int i = 7; i >= 2; i--) {
    while (freq[i] != 0) {
      cout << i;
      int val = fact(i);
      for (int p = 2; p < 8; p++) {
        while (val % p == 0) {
          freq[p]--;
          val /= p;
        }
      }
    }
  }
  cout << endl;
  return 0;
}

```