#include <bits/stdc++.h>
using namespace std;
const int p[4][10] = {{0, 0, 1, 1, 3, 3, 4, 4, 7, 7},
                      {0, 0, 0, 1, 1, 1, 2, 2, 2, 4},
                      {0, 0, 0, 0, 0, 1, 1, 1, 1, 1},
                      {0, 0, 0, 0, 0, 0, 0, 1, 1, 1}};
int main() {
  int N;
  cin >> N;
  string a;
  cin >> a;
  int s[4] = {};
  for (int i = 0; i < N; ++i) {
    for (int j = 0; j < 4; ++j) {
      s[j] += p[j][a[i] - '0'];
    }
  }
  string r = "";
  for (int t = 0; t < 4; ++t) {
    char k = "7532"[t];
    int I = s[3 - t];
    for (int i = 0; i < I; ++i) {
      r += k;
      for (int j = 0; j < 4; ++j) s[j] -= p[j][k - '0'];
    }
  }
  cout << r << '\n';
  return 0;
}

### Prompt

Generate 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;
const int p[4][10] = {{0, 0, 1, 1, 3, 3, 4, 4, 7, 7},
                      {0, 0, 0, 1, 1, 1, 2, 2, 2, 4},
                      {0, 0, 0, 0, 0, 1, 1, 1, 1, 1},
                      {0, 0, 0, 0, 0, 0, 0, 1, 1, 1}};
int main() {
  int N;
  cin >> N;
  string a;
  cin >> a;
  int s[4] = {};
  for (int i = 0; i < N; ++i) {
    for (int j = 0; j < 4; ++j) {
      s[j] += p[j][a[i] - '0'];
    }
  }
  string r = "";
  for (int t = 0; t < 4; ++t) {
    char k = "7532"[t];
    int I = s[3 - t];
    for (int i = 0; i < I; ++i) {
      r += k;
      for (int j = 0; j < 4; ++j) s[j] -= p[j][k - '0'];
    }
  }
  cout << r << '\n';
  return 0;
}

```