#include <fstream>

using namespace std;
ifstream f ("deque.in");
ofstream g ("deque.out");
int n,i,k,a[100],b[100],p,x,s;
int main()
{f>>n>>k;
p=1;
   for(i=1;i<=n;i++);
   f>>a[i];
   for(i=1;i<=n;i++)
   {
       x=a[i];
       if(i==1)
       b[1]=1;
       else
       {   p++;
           if(a[i]<b[p])
           {
               p++;
               b[p]=i;
           }
           if(a[i]>b[p])
           {
               s=s+a[i-2];
               a[i-1]=a[i-2]=0;

           }
        }
           if(k-p>i)
           p=p-k;


   }
g<<s<<'\n';
    return 0;
}