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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php

list($n, $m) = array_map("intval", explode(" ", fgets(STDIN)));
$dp[0] = 0;

$c = explode(",", "999,2,5,5,4,5,6,3,7,6");

$aArray = array_map("intval", explode(" ", fgets(STDIN)));
rsort($aArray);

for($i = 1; $i <= $n; $i++){
    foreach($aArray as $a){
        if(isset($dp[$i - $c[$a]])){
            if(@$dp[$i] < $dp[$i - $c[$a]] + 1){
                $dp[$i] = $dp[$i - $c[$a]] + 1;
            }
        }
    }
}
while($n > 0){
    foreach($aArray as $a){
        if(isset($dp[$n - $c[$a]])){
            if($dp[$n - $c[$a]] == $dp[$n] - 1){
                $n-=$c[$a];
                echo $a;
                break;
            }
        }
    }
}