#include <bits/stdc++.h>
using namespace std;
template <typename T>
struct Segtree {
  int n;
  T e;
  vector<T> dat;
  typedef function<T(T a, T b)> Func;
  Func f;
  Segtree() {}
  Segtree(int n_input, Func f_input, T e_input) {
    initialize(n_input, f_input, e_input);
  }
  void initialize(int n_input, Func f_input, T e_input) {
    f = f_input;
    e = e_input;
    n = 1;
    while (n < n_input) n <<= 1;
    dat.resize(2 * n - 1, e);
  }
  void update(int k, T a) {
    k += n - 1;
    dat[k] = a;
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = f(dat[2 * k + 1], dat[2 * k + 2]);
    }
  }
  T get(int k) { return dat[k + n - 1]; }
  T between(int a, int b) { return query(a, b + 1, 0, 0, n); }
  T query(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) return e;
    if (a <= l && r <= b) return dat[k];
    T vl = query(a, b, 2 * k + 1, l, (l + r) / 2);
    T vr = query(a, b, 2 * k + 2, (l + r) / 2, r);
    return f(vl, vr);
  }
};
void chmin(int64_t& a, int64_t b) { a = min(a, b); }
int main() {
  int N, C, A[100000];
  cin >> N >> C;
  for (int i = 0; i < N; i++) cin >> A[i];
  Segtree<int> st(
      N, [](int a, int b) { return min(a, b); }, 1e9);
  Segtree<int64_t> sum(
      N, [](int64_t a, int64_t b) { return a + b; }, 0);
  for (int i = 0; i < N; i++) {
    st.update(i, A[i]);
    sum.update(i, A[i]);
  }
  vector<int64_t> dp(N + 1, 1e18);
  dp[0] = 0;
  for (int i = 0; i < N; i++) {
    chmin(dp[i + 1], dp[i] + A[i]);
    if (i + C <= N)
      chmin(dp[i + C],
            dp[i] + sum.between(i, i + C - 1) - st.between(i, i + C - 1));
  }
  cout << dp[N] << endl;
  return 0;
}
