#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0, f = 1, c = getchar();
  for (; c < 48; c = getchar())
    if (c == '-') f = 0;
  for (; c >= 48; c = getchar()) x = x * 10 + c - '0';
  return f ? x : -x;
}
int main() {
  map<int, int> mp[10];
  for (int i = 2; i <= 9; ++i) {
    int x = i;
    for (int j = 2; j * j <= x; ++j) {
      if (x % j == 0) {
        while (x % j == 0) {
          mp[i][j]++;
          x /= j;
        }
      }
    }
    if (x > 1) {
      mp[i][x]++;
    }
  }
  int n = read();
  string a;
  cin >> a;
  map<int, int> tot;
  for (int i = 0; i < n; ++i) {
    if (a[i] >= '2')
      for (char c = '2'; c <= a[i]; ++c)
        for (auto p : mp[c - '0']) tot[p.first] += p.second;
  }
  string ans;
  if (tot[7]) ans += string(tot[7], '7');
  if (tot[5]) ans += string(tot[5] - tot[7], '5');
  for (int i = 0; i < ans.size(); ++i) {
    for (char c = '2'; c <= ans[i]; ++c)
      for (auto p : mp[c - '0']) tot[p.first] -= p.second;
  }
  if (tot[3]) ans += string(tot[3], '3');
  if (tot[2]) ans += string(tot[2] - tot[3], '2');
  cout << ans << endl;
  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;
inline int read() {
  int x = 0, f = 1, c = getchar();
  for (; c < 48; c = getchar())
    if (c == '-') f = 0;
  for (; c >= 48; c = getchar()) x = x * 10 + c - '0';
  return f ? x : -x;
}
int main() {
  map<int, int> mp[10];
  for (int i = 2; i <= 9; ++i) {
    int x = i;
    for (int j = 2; j * j <= x; ++j) {
      if (x % j == 0) {
        while (x % j == 0) {
          mp[i][j]++;
          x /= j;
        }
      }
    }
    if (x > 1) {
      mp[i][x]++;
    }
  }
  int n = read();
  string a;
  cin >> a;
  map<int, int> tot;
  for (int i = 0; i < n; ++i) {
    if (a[i] >= '2')
      for (char c = '2'; c <= a[i]; ++c)
        for (auto p : mp[c - '0']) tot[p.first] += p.second;
  }
  string ans;
  if (tot[7]) ans += string(tot[7], '7');
  if (tot[5]) ans += string(tot[5] - tot[7], '5');
  for (int i = 0; i < ans.size(); ++i) {
    for (char c = '2'; c <= ans[i]; ++c)
      for (auto p : mp[c - '0']) tot[p.first] -= p.second;
  }
  if (tot[3]) ans += string(tot[3], '3');
  if (tot[2]) ans += string(tot[2] - tot[3], '2');
  cout << ans << endl;
  return 0;
}

```