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())
hon=[2,5,5,4,5,6,3,7,6]
a=list(map(int, input().split()))
s=sorted(set([hon[i-1] for i in a]))
t=[0]*10
for i in range(9):
    if i+1 in a:t[hon[i]]=i+1
if len(s)>1:x=s[0]*s[1]+1
else:x=n
dp=[[-100]*(x+1) for i in range(len(s)+1)]
for i in range(1,len(s)+1):
    for j in range(x+1):
        if j%s[i-1]==0:
            dp[i][j]=max(dp[i][j],j//s[i-1])
        for k in range(1,j+1):
            if (j-k)%s[i-1]==0:
                dp[i][j]=max(dp[i][j],(j-k)//s[i-1]+dp[i-1][k])
ans=[]
if n>x:
    ans+=[min(s)]*-(-(n-x)//min(s))
    n=n+(-(n-x)//min(s))*min(s)
from itertools import product
for i in product(s,repeat=dp[-1][n]):
    if sum(i)==n:break
ans+=list(i)
import bisect
ansf=[]
for i in ans:
    bisect.insort_left(ansf,t[i])
print(*ansf[::-1],sep='')