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: Runtime Error)

priority = [1,7,4,5,3,2,9,6,8]
cost = [2,3,4,5,5,5,6,6,7]
n,m = gets.chomp.split.map(&:to_i)
a = gets.chomp.split.map(&:to_i)

choise = []

priority.each_with_index do |pri,i|
    if a.include?(pri) && !choise.include?(cost[i])
        choise.push([cost[i],pri])
    end
end

def seek_combination(cur,choise,crumb,n)
    choise.each do |c|
        if (cur+c[0]) == n
            cur += c[0]
            crumb.push(c)
            return crumb
        elsif (cur+c[0]) > n
            next
        else
            cur += c[0]
            crumb.push(c)
            res = seek_combination(cur,choise,crumb,n)
            if res
                return res
            end
            cur -= c[0]
            crumb.pop
        end
    end
    return nil
end

crumb = []
crumb = seek_combination(0,choise,crumb,n)
puts crumb.map{|i| i[1]}.sort.reverse.join('')