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 PyPy3 (2.4.0) (judge verdict: Time Limit Exceeded)

# -*- coding: utf-8 -*-

import sys, re
from collections import deque, defaultdict, Counter
from math import sqrt, hypot, factorial, pi, sin, cos, radians, log10
if sys.version_info.minor >= 5: from math import gcd
else: from fractions import gcd 
from heapq import heappop, heappush, heapify, heappushpop
from bisect import bisect_left, bisect_right
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul, xor
from copy import copy, deepcopy
from functools import reduce, partial
from fractions import Fraction
from string import ascii_lowercase, ascii_uppercase, digits

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def round(x): return int((x*2+1) // 2)
def fermat(x, y, MOD): return x * pow(y, MOD-2, MOD) % MOD
def lcm(x, y): return (x * y) // gcd(x, y)
def lcm_list(nums): return reduce(lcm, nums, 1)
def gcd_list(nums): return reduce(gcd, nums, nums[0])
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N, M = MAP()
A = LIST()
need = [0,2,5,5,4,5,6,3,7,6]

dp = [''] * (N+10)
for a in A:
    dp[need[a]] = max(dp[need[a]], str(a))

for i in range(N):
    if dp[i] != '':
        for a in A:
            # 基本は文字列の長さ(桁数)で比較
            if len(dp[i+need[a]]) < len(dp[i])+1:
                dp[i+need[a]] = dp[i]+str(a)
            # それが同じ時だけ数値変換して大小比較
            elif len(dp[i+need[a]]) == len(dp[i])+1:
                b = int(''.join(sorted(dp[i]+str(a), reverse=True)))
                c = int(''.join(sorted(dp[i+need[a]], reverse=True)))
                dp[i+need[a]] = str(max(b, c))
print(''.join(sorted(dp[N], reverse=True)))