#include <bits/stdc++.h>
using namespace std;
int fact[10][10];
int pr[10];
vector<int> num;
void f() {
  int i, j, k;
  for (i = 1; i <= 7; i++) {
    for (j = 2; j <= i; j++) {
      k = j;
      while (k % 2 == 0) {
        fact[i][2]++;
        k /= 2;
      }
      while (k % 3 == 0) {
        fact[i][3]++;
        k /= 3;
      }
      while (k % 5 == 0) {
        fact[i][5]++;
        k /= 5;
      }
      while (k % 7 == 0) {
        fact[i][7]++;
        k /= 7;
      }
    }
  }
}
void p(int n) {
  int i, j, k;
  for (j = 2; j <= n; j++) {
    k = j;
    while (k % 2 == 0) {
      pr[2]++;
      k /= 2;
    }
    while (k % 3 == 0) {
      pr[3]++;
      k /= 3;
    }
    while (k % 5 == 0) {
      pr[5]++;
      k /= 5;
    }
    while (k % 7 == 0) {
      pr[7]++;
      k /= 7;
    }
  }
}
int main() {
  int i, j, k, n, m, r;
  string s;
  cin >> n >> s;
  f();
  for (i = 0; i < s.length(); i++) {
    if (s[i] == '0')
      continue;
    else
      p(s[i] - '0');
  }
  for (i = 7; i >= 2; i--) {
    if (pr[i] != 0) {
      k = pr[i];
      for (j = 2; j <= 7; j++) {
        pr[j] -= k * fact[i][j];
      }
      for (r = 1; r <= k; r++) num.push_back(i);
    }
  }
  sort(num.begin(), num.end());
  for (i = num.size() - 1; i >= 0; i--) cout << num[i];
  cout << endl;
  return 0;
}

### Prompt

Your challenge is to write 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 fact[10][10];
int pr[10];
vector<int> num;
void f() {
  int i, j, k;
  for (i = 1; i <= 7; i++) {
    for (j = 2; j <= i; j++) {
      k = j;
      while (k % 2 == 0) {
        fact[i][2]++;
        k /= 2;
      }
      while (k % 3 == 0) {
        fact[i][3]++;
        k /= 3;
      }
      while (k % 5 == 0) {
        fact[i][5]++;
        k /= 5;
      }
      while (k % 7 == 0) {
        fact[i][7]++;
        k /= 7;
      }
    }
  }
}
void p(int n) {
  int i, j, k;
  for (j = 2; j <= n; j++) {
    k = j;
    while (k % 2 == 0) {
      pr[2]++;
      k /= 2;
    }
    while (k % 3 == 0) {
      pr[3]++;
      k /= 3;
    }
    while (k % 5 == 0) {
      pr[5]++;
      k /= 5;
    }
    while (k % 7 == 0) {
      pr[7]++;
      k /= 7;
    }
  }
}
int main() {
  int i, j, k, n, m, r;
  string s;
  cin >> n >> s;
  f();
  for (i = 0; i < s.length(); i++) {
    if (s[i] == '0')
      continue;
    else
      p(s[i] - '0');
  }
  for (i = 7; i >= 2; i--) {
    if (pr[i] != 0) {
      k = pr[i];
      for (j = 2; j <= 7; j++) {
        pr[j] -= k * fact[i][j];
      }
      for (r = 1; r <= k; r++) num.push_back(i);
    }
  }
  sort(num.begin(), num.end());
  for (i = num.size() - 1; i >= 0; i--) cout << num[i];
  cout << endl;
  return 0;
}

```