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 = [int(a) for a in input().split()]
if 1 in A:
    if 4 in A: A.remove(4)
    if 6 in A: A.remove(6)
    if 9 in A: A.remove(9)
if 3 in A:
    if 2 in A: A.remove(2)
if 5 in A:
    if 3 in A: A.remove(3)
    if 2 in A: A.remove(2)
if 7 in A:
    if 6 in A: A.remove(6)
    if 9 in A: A.remove(9)
if 9 in A:
    if 6 in A: A.remove(6)

def MatchNum(i):
    if i == 1: return 2
    elif i == 4: return 4
    elif i in [2, 3, 5]: return 5
    elif i == 7: return 3
    elif i == 8: return 7
    elif i in [6, 9]: return 6

DP = [""] * (N+1)
for key in A:
    DP[MatchNum(key)] = str(key)

for i in range(1, N):
    if DP[i]:
        for key in A:
            if i + MatchNum(key) <= N:
                if not DP[i + MatchNum(key)]:  DP[i + MatchNum(key)] = str(key) + DP[i] 
                elif int(DP[i + MatchNum(key)]) < int(str(key) + DP[i]):
                    DP[i + MatchNum(key)] = str(key) + DP[i]
print(DP[N])