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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val (n,m) = readLine()!!.split(" ").map { it.toInt() }
    val a = readLine()!!.split(" ").map { it.toInt() }.sorted()
    val match = intArrayOf(0,2,5,5,4,5,6,3,7,6)

    val dp = IntArray(n+10){-1}
    dp[0] = 0
    repeat(n) { i ->
        a.forEach { dp[i+match[it]] = Math.max(dp[i+match[it]], dp[i] + 1 ) }
    }

    var ans = ""
    var l = n
    while(ans.length<dp[n]) {
        val num = a.last { if (l-match[it]<0) false else dp[l-match[it]] == dp[l]-1 }
        ans += num
        l -= match[num]
    }
    println(ans)

}