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 Julia (0.5.0) (judge verdict: Accepted)

parseInt(x) = parse(Int, x)
parseMap(x::Array{SubString{String},1}) = map(parseInt, x)

function main()
	v = [2,5,5,4,5,6,3,7,6]
	n,m = readline() |> split |> parseMap
	a = readline() |> split |> parseMap
	a = sort(a,rev=true)
	dp = -ones(Int,n+1)
	dp[1] = 0
	for i in 1:n+1
		if dp[i]>=0
			for j in a
				if i+v[j]<=n+1
					dp[i+v[j]]=max(dp[i+v[j]],dp[i]+1)
				end
			end
		end
	end
	k = n+1
	while k>1
		for j in a
			if k-v[j]>0
				if dp[k-v[j]]==dp[k]-1
					print(j)
					k -= v[j]
					break
				end
			end
		end
	end
	println("")
end

main()