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: Accepted)

io = STDIN
N,_=io.gets.split.map(&:to_i)
a=io.gets.split.map(&:to_i)
#      1 2 3 4 5 6 7 8 9
$ar=[0,2,5,5,4,5,6,3,7,6]  #各数字の本数
#          - -     - -
$dp=Array.new(N+10)
$dp[0]=0
#                    1 1 1 1 1 1 1 1 1 1
#0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
#
(0..N).each do |i|
  a.each do |num|  #num  3 7 8 4
                   #m    5 3 7 4
    m=$ar[num] #m:本数
    # p ["num,m,i,$dp[i]*10+num,$dp[i+m]",num,m,i,$dp[i]*10+num,$dp[i+m]]
    next if  $dp[i]==nil
    if $dp[i+m]==nil || $dp[i]*10+num > $dp[i+m]
      $dp[i+m]=$dp[i]*10+num
    end
  end
end
p $dp[N]