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>
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.StringWriter;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author HossamDoma
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {


            int n = in.nextInt();
            char[] s = in.next().toCharArray();

            int[] fact = new int[10];
            fact[0] = fact[1] = 1;
            for (int i = 2; i <= 9; ++i)
                fact[i] = fact[i - 1] * i;

            int[] primes = new int[]{2, 3, 5, 7};

            String[] bst = new String[10];

            for (int i = 2; i <= 9; ++i) {

                bst[i] = String.valueOf(i);

                for (int k = primes.length - 1; k >= 0; --k) {

                    int p = primes[k];

                    if (p == i) break;

                    if (p < i) { //immediate predecessor

                        int rem = fact[i] / fact[p];

                        String x = String.valueOf(p);

                        while (--k >= 0) {
                            while (rem % fact[primes[k]] == 0) {
                                x += (char) ('0' + primes[k]);
                                rem /= fact[primes[k]];
                            }
                        }

                        if (x.length() > bst[i].length())
                            bst[i] = x;

                        break;
                    }
                }
            }


            StringWriter sw = new StringWriter();

            for (int i = 0; i < s.length; ++i) {

                if (s[i] == '1' || s[i] == '0') continue;

                sw.append(bst[s[i] - '0']);
            }

            char[] ans = sw.toString().toCharArray();

            Arrays.sort(ans);

            for (int i = ans.length - 1; i >= 0; --i)
                out.print(ans[i]);

        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }
}

