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)

N,M=map(x->parse(Int,x),split(readline()))
A=sort(map(x->parse(Int,x),split(readline())))
num=[2,5,5,4,5,6,3,7,6]
dp=Array{Int}(N+1)
dp[1]=0
for i=1:N
	ret=-10^10
	for a=A
		if num[a]<=i
			ret=max(ret,dp[i-num[a]+1]+1)
		end
	end
	dp[i+1]=ret
end
id=N+1
while id>1
	now=-1
	for a=A
		if id>num[a]&&dp[id-num[a]]+1==dp[id]
			now=a
		end
	end
	print(now)
	id-=num[now]
end
println()