Drazil is playing a math game with Varda.

Let's define  for positive integer x as a product of factorials of its digits. For example, .

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.  = .

Help friends find such number.

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 a maximum possible integer satisfying the conditions above. There should be no zeroes and ones in this number decimal representation.

#include <iostream>

#include <cstdio>

#include <algorithm>

#include <cmath>

#include <stack>

#include <vector>

#include <queue>

#include <cstring>

#include <string>

#include <map>

#include <set>

using namespace std;

const int BufferSize = 1 << 16;

char buffer[BufferSize], *Head, *Tail;

inline char Getchar() {

    if(Head == Tail) {

        int l = fread(buffer, 1, BufferSize, stdin);

        Tail = (Head = buffer) + l;

    }

    return *Head++;

}

int read() {

    int x = 0, f = 1; char c = getchar();

    while(!isdigit(c)){ if(c == '-') f = -1; c = getchar(); }

    while(isdigit(c)){ x = x * 10 + c - '0'; c = getchar(); }

    return x * f;

}

#define maxn 6000010

#define maxk 20

int n, sum, fact[maxk], F[maxn], f[maxn][11];

char num[maxk];

bool vis[maxn];

bool Less(int* a, int* b) {

	for(int i = 9; i >= 2; i--) if(a[i] != b[i])

		return a[i] < b[i];

	return 0;

}

int main() {

	n = read();

	scanf("%s", num + 1);

	fact[0] = 1;

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

	sum = 1;

	for(int i = 1; i <= n; i++) sum *= fact[num[i]-'0'];

	vis[1] = 1;

	for(int i = 1; i <= sum; i++) if(vis[i]) {

//		printf("%d ", i);

		for(int k = 2; k <= 9 && fact[k] * i <= sum; k++) {

			int t = fact[k] * i;

//			printf("[%d]", t);

			vis[t] = 1;

			if(F[t] < F[i] + 1) {

				F[t] = F[i] + 1;

				memcpy(f[t], f[i], sizeof(f[i]));

				f[t][k]++;

			}

			if(F[t] > F[i] + 1) continue;

			f[i][k]++;

			if(Less(f[t], f[i])) memcpy(f[t], f[i], sizeof(f[i]));

			f[i][k]--;

		}

	}

	for(int i = 9; i >= 2; i--)

		for(int j = 1; j <= f[sum][i]; j++)

			putchar(i + '0');

	putchar('\n');

	return 0;

}

#include <iostream>

#include <cstdio>

#include <algorithm>

#include <cmath>

#include <stack>

#include <vector>

#include <queue>

#include <cstring>

#include <string>

#include <map>

#include <set>

using namespace std;

const int BufferSize = 1 << 16;

char buffer[BufferSize], *Head, *Tail;

inline char Getchar() {

    if(Head == Tail) {

        int l = fread(buffer, 1, BufferSize, stdin);

        Tail = (Head = buffer) + l;

    }

    return *Head++;

}

int read() {

    int x = 0, f = 1; char c = getchar();

    while(!isdigit(c)){ if(c == '-') f = -1; c = getchar(); }

    while(isdigit(c)){ x = x * 10 + c - '0'; c = getchar(); }

    return x * f;

}

#define maxn 20

int n, cnt[maxn];

char num[maxn];

int main() {

	n = read();

	scanf("%s", num + 1);

	for(int i = 1; i <= n; i++) {

		if(num[i] == '9') {

			cnt[7]++; cnt[3]++; cnt[3]++; cnt[2]++;

		}

		if(num[i] == '8') {

			cnt[7]++; cnt[2]++; cnt[2]++; cnt[2]++;

		}

		if(num[i] == '7') {

			cnt[7]++;

		}

		if(num[i] == '6') {

			cnt[5]++; cnt[3]++;

		}

		if(num[i] == '5') {

			cnt[5]++;

		}

		if(num[i] == '4') {

			cnt[3]++; cnt[2]++; cnt[2]++;

		}

		if(num[i] == '3') {

			cnt[3]++;

		}

		if(num[i] == '2') {

			cnt[2]++;

		}

	}

	for(int i = 7; i >= 2; i--)

		for(int j = 1; j <= cnt[i]; j++) putchar(i + '0');

	putchar('\n');

	return 0;

}