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: Wrong Answer)

#include <iostream> // cin, cout, cerr, clog
#include <algorithm> // minmax, sort, swap
#include <numeric> // iota, accumulate, inner_product
#include <cstdio> // printf, scanf
#include <climits> // INT_MIN, LLONG_MIN
#include <cmath> // long, trig, pow
#include <string> // string, stoi, to_string
#include <vector> // vector
#include <queue> // queue, priority_queue
#include <stack> // stack
#include <map> // key-value pairs sorted by keys
#include <set> // set
#include <unordered_map> // hashed by keys
#include <unordered_set> // hashed by keys
#include <iomanip> // cout<<setprecision(n)

#define rep(i,n) for(int i = 0; i < n; i++)
#define ENDL "\n"
#define print(i) std::cout << (i) << "\n"

#define int long long // at least int64 > 9*10^18
#define all(v) v.begin(), v.end()
#define INF 10101010

signed main() {
	int n,m;
	std::cin >> n >> m;
	std::vector<int> a(m);
	rep(i,m) std::cin >> a[i];
	int mc[10] = {0,2,5,5,4,5,6,3,7,6};
	std::vector<std::vector<int> > dp(n+1,std::vector<int>(10,-INF));
	dp[0] = std::vector<int>(10,0);
	for(auto& i:a) {
		for(int j=0;j<=n-mc[i];j++) {
			if(dp[j][0]==-INF) continue;
			if(dp[mc[i]+j][0] <= dp[j][0]+1) {
				dp[mc[i]+j] = dp[j];
				dp[mc[i]+j][0]++;
				dp[mc[i]+j][i]++;
			}
		}
	}
	std::string ans = "";
	for(int i=1;i<=9;i++) {
		while(dp[n][i]>0) {
			ans = std::to_string(i) + ans;
			dp[n][i]--;
		}
	}
	print(ans);
	return 0;
}