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()))

inf = float("inf")
dp = [-inf for i in range(n+1)]
dp[0] = 0

cost = {1:2, 2:5, 3:5, 4:4, 5:5, 6:6, 7:3, 8:7, 9:6}
use_cost = []
for i in a:
    use_cost.append(cost[i])
    for j in range(1, n+1):
        if j - cost[i] >= 0:
            dp[j] = max(dp[j], dp[j-cost[i]]+1)

if n < min(use_cost):
    print(0)
    exit()

a.sort(reverse=True)
ans = ""
while n > 0:
    for i in a:
        if dp[n-cost[i]] == dp[n]-1:
            ans += str(i)
            n -= cost[i]
            break
print(ans)