#include <bits/stdc++.h>
using namespace std;
int Facteurs[4];
int Liste[4] = {2, 3, 5, 7};
void DetermineFacteur(string s) {
  for (int j = 0; j < 4; j++) Facteurs[j] = 0;
  for (int i = 0; i < (int)s.length(); i++) {
    int cur = s[i] - '0';
    int facto = 1;
    for (int l = 2; l <= cur; l++) facto *= l;
    for (int j = 0; j < 4; j++) {
      while (facto % Liste[j] == 0) {
        facto /= Liste[j];
        Facteurs[j]++;
      }
    }
  }
}
int CombienRetirer[4][4];
void Solve() {
  for (int i = 0; i < 4; i++)
    for (int j = 0; j < 4; j++) {
      if (j <= i)
        CombienRetirer[i][j] = 1;
      else
        CombienRetirer[i][j] = 0;
    }
  CombienRetirer[2][0] = 3;
  CombienRetirer[3][0] = 4;
  CombienRetirer[3][1] = 2;
  for (int i = 3; i >= 0; i--) {
    for (int l = 0; l < Facteurs[i]; l++) cout << Liste[i];
    for (int j = 0; j < 4; j++) {
      Facteurs[j] -= (CombienRetirer[i][j] * Facteurs[i]);
    }
  }
}
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  DetermineFacteur(s);
  Solve();
}

### 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;
int Facteurs[4];
int Liste[4] = {2, 3, 5, 7};
void DetermineFacteur(string s) {
  for (int j = 0; j < 4; j++) Facteurs[j] = 0;
  for (int i = 0; i < (int)s.length(); i++) {
    int cur = s[i] - '0';
    int facto = 1;
    for (int l = 2; l <= cur; l++) facto *= l;
    for (int j = 0; j < 4; j++) {
      while (facto % Liste[j] == 0) {
        facto /= Liste[j];
        Facteurs[j]++;
      }
    }
  }
}
int CombienRetirer[4][4];
void Solve() {
  for (int i = 0; i < 4; i++)
    for (int j = 0; j < 4; j++) {
      if (j <= i)
        CombienRetirer[i][j] = 1;
      else
        CombienRetirer[i][j] = 0;
    }
  CombienRetirer[2][0] = 3;
  CombienRetirer[3][0] = 4;
  CombienRetirer[3][1] = 2;
  for (int i = 3; i >= 0; i--) {
    for (int l = 0; l < Facteurs[i]; l++) cout << Liste[i];
    for (int j = 0; j < 4; j++) {
      Facteurs[j] -= (CombienRetirer[i][j] * Facteurs[i]);
    }
  }
}
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  DetermineFacteur(s);
  Solve();
}

```