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 = list( map( int, input().split()))
C = [0,2,5,5,4,5,6,3,7,6]
dp = [(0,0)]*(N+1)
for a in A:
    dp[C[a]] = (1,0)
Z = sorted( list( set( C[a] for a in A)))
for i in range(2,N+1):
    for z in Z:
        if i > z:
            if dp[i-z][0] == 1:
                dp[i] = (1, i-z)
                break
s = N
ANS = [0]*10
while s != 0:
    _, b = dp[s]
    ANS[s-b] += 1
    s = b
ans = ""
for i in range(9,0,-1):
    if ANS[C[i]] > 0:
        if i in A:
            ans = ans + str(i)*ANS[C[i]]
            ANS[C[i]] = 0
print( ans)