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: Wrong Answer)

n, m = list(map(int, input().split()))
li = list(map(int, input().split()))
di = {}
for i, d in enumerate([2,5,5,4,5,6,3,7,6], 1):
    di[i] = d
li.sort(reverse=True)
hons = set(di[a] for a in li)
dd = {}
for a in li:
    hon = di[a]
    if hon not in dd:
        dd[hon] = a

h2d = [0]
pre = [None]
for i in range(1, n + 1):
    res = -float('inf')
    p = None
    for hon in hons:
        if i < hon:
            continue
        dig = h2d[i - hon] + 1
        if dig > res:
            res = dig
            p = i - hon
    h2d.append(res)
    pre.append(p)

ans = []
while n > 0:
    ans.append(dd[n - pre[n]])
    n = pre[n]
ans.sort(reverse=True)
print(*ans, sep='')