#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const ll INF = 1e18;

struct RminQ {
  int m;
  vector<long long> dat;
 
  RminQ(int n) {
    m = 1;
    while (m < n) m *= 2;
 
    dat.assign(2 * m - 1, INF);
  }
 
  void update(int i, long long x) {
    i += m - 1;
    dat[i] = x;
 
    while (i) {
      i = (i - 1) / 2;
      dat[i] = min(dat[i * 2 + 1], dat[i * 2 + 2]);
    }
  }
 
  // [a, b)
  long long query(int a, int b, int k, int l, int r) {
    if (l >= b || r <= a) return INF;
    if (a <= l && r <= b) return dat[k];
    
    long long vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
    long long vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
 
    return min(vl, vr);
  }
 
  long long query_sub(int a, int b) {
    return query(a, b, 0, 0, m);
  }
};

int main(void) {
  ll n, k;
  cin >> n >> k;

  vector<ll> a(n+2);
  for (int i = 1; i <= n; ++i) cin >> a[i];

  a[0] = a[n+1] = 0;

  RminQ rmq(n+5);
  rmq.update(0, 0);

  for (int i = 1; i < n+2; ++i) {
    rmq.update(i, rmq.query_sub(i-k, i) + a[i]);
  }

  cout << accumulate(begin(a), end(a), 0LL) - rmq.query_sub(n+1, n+2) << endl;

  return 0;
}