#include <bits/stdc++.h>
using namespace std;
#define ll long long int
const int M = 1e9 + 7;
 
//Microsoft OA 21 Aug
 
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
 
    int n, k;
    cin >> n >> k;
    vector<int> v(n);
    for (int i = 0; i < n; i++)
        cin >> v[i];
    multiset<int> st;
    st.insert(0);
    vector<int> dp(n);
    for (int i = 1; i < n; i++)
    {
        int mi = *st.begin();
        dp[i] = v[i] + mi;
        st.insert(dp[i]);
        if (st.size() > k)
            st.erase(dp[i-k]);
    }
 
    cout << dp[n - 1] << endl;
    return 0;
}

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NyAyCjEgMiA1IDUgMSAxIDY=

7 2
1 2 5 5 1 1 6