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: Wrong Answer)

import sys
sys.setrecursionlimit(999999)
dicte = {1:2, 2:5, 3:5, 4:4, 5:5, 6:6, 7:3, 8:7, 9:6}
n, m = map(int, input().split())
arr = list(map(int, input().split()))
dp = [-1 for i in range(n+1)]
def cast(a, b):
    return int(str(a)+str(b))
def solve(curn):
    maxi = -1
    if dp[curn] != -1:
        return dp[curn]

    for j in arr:
        if curn - dicte[j] >= 0:
            dp[curn-dicte[j]] = solve(curn-dicte[j])
            if dp[curn-dicte[j]] == None:
                maxi = max(j, maxi)
            else:
                maxi = max(cast(j, dp[curn-dicte[j]]), maxi)
    if maxi == -1:
        return None
    return maxi
print(solve(n))