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()))
seg0=[0,2,5,5,4,5,6,3,7,6]

A.sort(reverse=1)
seg=[]
for i in range(m):
    seg.append(seg0[A[i]])

#print(seg)

keta=[0 for i in range(n+1)]
for i in range(1,n+1):
    for j in range(m):
        if i-seg[j]>=0 :
            keta[i]=max(keta[i],keta[i-seg[j]]+1)

#print(keta)

ke=keta[n]

#print(ke)
#print(seg)
ans=0
while ke>1 :
    for j in range(m):
        #print(n-seg[j])
        #print(keta[n-seg[j]])
        if n-seg[j]>0 and keta[n]==keta[n-seg[j]]+1 :
            ans+=A[j]*10**(ke-1)
            n-=seg[j]
            #print(ans)
            break
    ke-=1

#print(n)
for i in range(m):
    #print(keta[n])
    if n==seg[i] :
        ans+=A[i]

print(ans)