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 C (GCC 5.4.1) (judge verdict: Runtime Error)

#include<stdio.h>
int MAX(int a,int b){return a<b?b:a;}
int main(){
  int d[510][1010],b[]={0,2,5,5,4,5,6,3,7,6};
  int i,j,k,n,m,mi,a[10]={};
  scanf("%d %d",&n,&m);
  for(i=0;i<m;i++){
    scanf("%d",&j);
    a[j]=1;
  }//printf("a\n");
  d[0][n]=1;
  for(i=0;i<510;i++){//printf("%d\n",i);
    for(j=0;j<=n;j++){
      if(d[i][j]==0)continue;
      for(k=0;k<10;k++){
	if(a[k]==0||b[k]>j)continue;
	d[i+1][j-b[k]]=MAX(d[i+1][j-b[k]],k);
	mi=i+1;
      }
    }
  }
  /*for(i=0;i<=mi;i++){
    for(j=0;j<=n;j++)printf("%d ",d[i][j]);printf("\n");
    }//*/
  for(j=0;mi;mi--){
    printf("%d",d[mi][j]);
    j+=b[d[mi][j]];
  }
  printf("\n");
  return 0;
}