#include <iostream>
#include <fstream>
using namespace std;
ifstream f("deque.in");
ofstream g("deque.out");
int main()
{
    long i, j, k, n, suma, coada[5000001], x;

    f>>n>>k;

    for(i=0;i<n;i++)
    {
        f>>x;

        if(i==0)
        {
            coada[i] = x;
            j = i;
        }
        else
        {
            while(coada[j]>x && j>=i-k+1 && j>=0)
            {
                coada[j] = x;
                j--;
            }
            j = i;
            coada[j] = x;
        }
    }

    suma = 0;

    for(i=0;i<n-k+1;i++)
        suma += coada[i];
    g<<suma;
}