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)

ort math

N,M=map(int,input().split())
A=list(map(int,input().split()))
A.sort(reverse=True)
num=[0,2,5,5,4,5,6,3,7,6]
dp=[0]
keta=[0]
tmp=0
tmp1=0
tmp_keta=-1
tmp1_keta=-1
for i in range(1,N+1):
    tmp=-100000000000000000000
    tmp_keta=-1
    for j in A:
        tmp1=-100000000000000000000
        tmp1_keta=-1
        if(i-num[j]>=0):
            if(dp[i-num[j]]!=0):
                tmp1=dp[i-num[j]]+j*(10**keta[i-num[j]])
                tmp1_keta=keta[i-num[j]]+1
            else:
                tmp1=j
                tmp1_keta=1
            if(tmp1>tmp):
                tmp=tmp1
                tmp_keta=tmp1_keta
    dp.append(tmp)
    keta.append(tmp_keta)
ans=dp[N]
print(ans)