#include <iostream>
#include <iosfwd>
#include <iomanip>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <cassert>
#include <cctype>
#include <climits>
#include <vector>
#include <bitset>
#include <set>
#include <queue>
#include <stack>
#include <map>
#include <deque>
#include <string>
#include <list>
#include <iterator>
#include <sstream>
#include <complex>
#include <fstream>
#include <functional>
#include <numeric>
#include <utility>
#include <algorithm>
#include <assert.h>
#include <unordered_map>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef double ld;
typedef vector < long long > vll;
typedef pair <long long, long long> pll;
typedef pair <int, int> pii;
typedef vector < int > vii;
typedef complex < double > Point;

#define csl ios_base::sync_with_stdio(false); cin.tie(NULL)
#define mp make_pair
#define fst first
#define snd second

ll t, n, m, u, v, q, r, ql, qr, k, l, s, w, z, x, y, d, p, c, L, b;
const int N = 2e5 + 500;
const int NN = 1e4 + 4;
const long long mod = 1e9 + 7;
const long long INF = 1LL << 52LL;

ll dp[N];
ll dp2[N];
ll A[N];
int main() {
    csl;
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) cin >> A[i];
    for (int i = 1; i <= n; ++i) {
        dp[i] = dp[max(0LL, i - k - 1)] + A[i];
        dp2[i] = dp[i];
        for (int j = max(1LL, i - k); j <= i - 1; ++j) {
            dp[i] = min(dp[i], min(dp2[j], dp[j] + A[j]));
            dp2[i] = min(dp2[i], min(dp[i], dp2[i]) + A[i]);
        }
    }
    cout << min(dp[n], dp2[n]) << '\n';
    return 0;
}