#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
    int p=0,k,n,a[10000],b[10000],i;
    cin>>k>>n;
    for(i=0;i<n-1;i++)
    {
        scanf("%d",&a[i]);
    }
    for(i=k-2;i<n-1;i+=k+1)
    {
        b[p++]=a[i];
    }
    if((n-1)%(k+1)+1!=0)b[p++]=a[n-2];
    printf("%d\n%d",p,b[p-1]);
    sort(b,b+p);
    for(i=p-2;i>=0;i--)
    printf(" %d",b[i]);
    printf("\n");
}
