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 = map(int, input().split())
A = list(map(int, input().split()))

import sys
INT_MIN = sys.maxsize * -1
match = [-100,2,5,5,4,5,6,3,7,6]
CHOICES = []
for i in A:
    if (i == 6) and (9 in A):
        continue
    if (i == 3) and (5 in A):
        continue
    if (i == 2) and (3 in A or 5 in A):
        continue
    CHOICES.append([i, match[i]])
CHOICES.sort(reverse=True)

ans = [0]
#print(CHOICES)
for i in range(1,N+1):
    ans.append(INT_MIN)
    for c in CHOICES:
        if  i - c[1] == 0:
            ans[i] = max(ans[i], int(str(c[0])))
            break
        elif i - c[1] >= 0 and ans[i - c[1]] != INT_MIN:
            ans[i] = max(ans[i], int(str(c[0]) + str(ans[i - c[1]])))
            break

print(ans[N])