#include <bits/stdc++.h>
using namespace std;
const long long N = 1 << 18;
const long long INF = 1000000000;
long long n, pr[10], g;
string t;
long long re(long long v, long long x) {
  long long s = 0;
  for (int i = 2; i <= v; i++) {
    g = i;
    while (g % x == 0) {
      s++;
      g /= x;
    }
  }
  return s;
}
void get(long long x) {
  if (x == 0 || x == 1) return;
  for (int i = 2; i <= x; i++) {
    g = i;
    for (int j = 2; j <= x; j++)
      while (g % j == 0) {
        pr[j]++;
        g /= j;
      }
  }
}
void upd(long long x, long long v) {
  for (int i = 2; i < 10; i++) pr[i] -= x * re(v, i);
}
int main() {
  cin >> n >> t;
  for (int i = 0; i < n; i++) {
    get(t[i] - '0');
  }
  for (int i = 1; i <= pr[7]; i++) cout << 7;
  upd(pr[7], 7);
  for (int i = 1; i <= pr[5]; i++) cout << 5;
  upd(pr[5], 5);
  for (int i = 1; i <= pr[3]; i++) cout << 3;
  upd(pr[3], 3);
  for (int i = 1; i <= pr[2]; i++) cout << 2;
  return 0;
}

### Prompt

Develop a solution in cpp to the problem described below:

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 long long N = 1 << 18;
const long long INF = 1000000000;
long long n, pr[10], g;
string t;
long long re(long long v, long long x) {
  long long s = 0;
  for (int i = 2; i <= v; i++) {
    g = i;
    while (g % x == 0) {
      s++;
      g /= x;
    }
  }
  return s;
}
void get(long long x) {
  if (x == 0 || x == 1) return;
  for (int i = 2; i <= x; i++) {
    g = i;
    for (int j = 2; j <= x; j++)
      while (g % j == 0) {
        pr[j]++;
        g /= j;
      }
  }
}
void upd(long long x, long long v) {
  for (int i = 2; i < 10; i++) pr[i] -= x * re(v, i);
}
int main() {
  cin >> n >> t;
  for (int i = 0; i < n; i++) {
    get(t[i] - '0');
  }
  for (int i = 1; i <= pr[7]; i++) cout << 7;
  upd(pr[7], 7);
  for (int i = 1; i <= pr[5]; i++) cout << 5;
  upd(pr[5], 5);
  for (int i = 1; i <= pr[3]; i++) cout << 3;
  upd(pr[3], 3);
  for (int i = 1; i <= pr[2]; i++) cout << 2;
  return 0;
}

```