Problem:
Score : 400 points

Problem Statement

Find the largest integer that can be formed with exactly N matchsticks, under the following conditions:

Every digit in the integer must be one of the digits A_1, A_2, ..., A_M (1 \leq A_i \leq 9).

The number of matchsticks used to form digits 1, 2, 3, 4, 5, 6, 7, 8, 9 should be 2, 5, 5, 4, 5, 6, 3, 7, 6, respectively.

Constraints

All values in input are integers.

2 \leq N \leq 10^4

1 \leq M \leq 9

1 \leq A_i \leq 9

A_i are all different.

There exists an integer that can be formed by exactly N matchsticks under the conditions.

Input

Input is given from Standard Input in the following format:

N M
A_1 A_2 ... A_M

Output

Print the largest integer that can be formed with exactly N matchsticks under the conditions in the problem statement.

Sample Input 1

20 4
3 7 8 4

Sample Output 1

777773

The integer 777773 can be formed with 3 + 3 + 3 + 3 + 3 + 5 = 20 matchsticks, and this is the largest integer that can be formed by 20 matchsticks under the conditions.

Sample Input 2

101 9
9 8 7 6 5 4 3 2 1

Sample Output 2

71111111111111111111111111111111111111111111111111

The output may not fit into a 64-bit integer type.

Sample Input 3

15 3
5 4 6

Sample Output 3

654

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

//#include "pch.h"
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
using namespace std;

#define FOR(i, s, e) for(int i=s; i<e; i++)
#define REF(i, s, e) for(int i=s; i>e; i--)
typedef long long ll;
static const string MinusINF = "-";


static const vector<int> vecMatch({ 2,5,5,4,5,6,3,7,6 });
int n_match, n_num;

int match(int num) {
	return vecMatch[num - 1];
}

void chmax(string& a, string b) {
	
	if (a == MinusINF) a = b;
	else if (a.size() < b.size()) a = b;
	else if (a.size() == b.size()) {
		if (a < b) a = b;
	}
	
}

int main(void) {
	cin.tie(0);
	ios::sync_with_stdio(false);


	cin >> n_match >> n_num;

	vector<int> nums(n_num);
	FOR(i, 0, n_num) cin >> nums[i];

	string dp[10010];
	FOR(i, 0, n_match) dp[i] = MinusINF;
	dp[0] = "";

	FOR(i, 0, n_match) {
		if (dp[i] == MinusINF) continue;
		for (int num : nums) chmax(dp[i + match(num)], dp[i] + (char)('0' + num));
	}

	//cout << "dp:" << endl;
	//FOR(i, 0, n_match+1) cout << dp[i] << endl;
	cout << dp[n_match] << endl;
}