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)

n_hsh = {
  	1 => 2,
  	2 => 5,
  	3 => 5,
    4 => 4,
  	5 => 5,
  	6 => 6,
  	7 => 3,
  	8 => 7,
  	9 => 6
  }

k_hsh = {
  	2 => [1],
  	3 => [7],
  	4 => [4],
  	5 => [2,3,5],
  	6 => [6,9],
  	7 => [8]
  }

n,m=gets.chomp.split(" ").map(&:to_i)
ary=gets.chomp.split(" ").map(&:to_i).sort.reverse

s_nums = ary.sort_by { |a| n_hsh[a] }
u_nums = s_nums.map { |s| n_hsh[s] }
flag = true
s,a = n.divmod(u_nums[0])
ans = []
s.times do |i|
  ans << s_nums[0]
end

if a == 0
  puts ans.join
else
  while a != 0 do
    tmp = ans.shift
    a = n_hsh[tmp] + a
    t_n = u_nums.take_while { |u| u <= a }.uniq
    a = a - t_n[-1]
    ans << s_nums[t_n.size-1]
  end
  puts ans.sort.reverse.join
end