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 Ruby (2.3.3) (judge verdict: Wrong Answer)

st = gets.chomp!.split(" ")
n = st[0].to_i

st = gets.chomp!.split(" ")
s = st.size-1
AMO = [nil,2,5,5,4,5,6,3,7,6]
num = Hash.new
ans = ""

for i in 0..s
    num[AMO[st[i].to_i]] = st[i].to_i
end

num = num.sort{|a,b| a[0] <=> b[0]}

if n >= num[0][0]
    (n/num[0][0]).times do
        ans += "#{num[0][1]}"
    end
end

n %= num[0][0]
x = num[0][0]
y = num[0][1]

num = num.sort{|a,b| -a[1] <=> -b[1]}
i = 0
j = 0

while n != 0
    if x == num[i][0]
        break
    end

    if n < num[i][0] - x
        i += 1
        next
    end

    ans[j] = "#{num[i][1]}"
    j += 1
    i += 1
    n -= num[i][0]-x
    redo
end

num = num.sort{|a,b| a[1] <=> b[1]}
i = 0
j = ans.size-1

while n != 0
    if x == num[i][0]
        break
    end

    if n < num[i][0] - x
        i += 1
        next
    end

    ans[j] = "#{num[i][1]}"
    j -= 1
    n -= num[i][0] - x
end

puts ans