#include <fstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <climits>
using namespace std;

int n, k;
int v[5000001];
multiset<int> elem;


ifstream fin("deque.in");
ofstream fout("deque.out");

int main()
{
    fin >> n >> k;
    int st = 1, dr = 0;
    int sum = 0;
    for (int i = 1; i <= n; i++)
    {
      
        fin >> v[i];
        if (dr - st == k-1)
        {
            //afisez cel mai mic elem si suma
            sum += *elem.begin();
            multiset<int>::iterator itr = elem.find(v[st]);
            elem.erase(itr);
            st++;
        }
        dr++;
        elem.insert(v[i]);
    }
    fout << sum;
    return 0;
}