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 Python (3.4.3) (judge verdict: Runtime Error)

N, M = map(int, input().split())
A = list(map(int, input().split()))
A.sort(reverse = True)

example = [2,5,5,4,5,6,3,7,6]
A_cost = [example[i-1] for i in A]

min_cost = min(A_cost)
min_bookmark = A_cost.index(min_cost)
num_standard = A[min_bookmark]
digit = N // min_cost
surplus = N - (digit * min_cost)
result = str(num_standard) * digit

now = 0
bookmark = 0
while surplus > 0:
    if A_cost[bookmark] - min_cost > surplus:
        bookmark += 1
        if bookmark == min_bookmark:
            break
        else:
            continue
    
    result = result[:now] + str(A[bookmark]) + result[now+1:]
    surplus -= A_cost[bookmark] - min_cost

    now += 1
    if now == digit:
        break

now = digit-1
big_cost = max(A_cost)
big_cost_num = A[A_cost.index(big_cost)]
while surplus > 0:
    cost = A_cost[A.index(int(result[now]))]
    if big_cost-cost <= surplus:
        surplus -= big_cost-cost
        result = result[:now] + str(big_cost_num) + result[now+1:]
        now -= 1
    else:
        big_cost -= 1
        while big_cost not in A_cost:
            big_cost -= 1
        big_cost_num = A[A_cost.index(big_cost)]
    
print(result)