

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.StringTokenizer;

 class Main {

	@SuppressWarnings("unused")
	public static void main(String[] args) {
		FastScanner in = new FastScanner();
//		int T = in.nextInt();
//		outer: for (int tt = 0; tt < T; tt++) {
//		}
		int n = in.nextInt();
		int k = in.nextInt();
		int a[] = in.readArray(n);
		int dp[] = new int[n + 1];
		Arrays.fill(dp, -1);
		System.out.println(frog2(dp, a, n - 1, k));
	}

	public static int frog2(int dp[], int a[], int N, int K) {
		if (N == 0)
			return 0;

		if (dp[N] != -1)
			return dp[N];
		int ans = Integer.MAX_VALUE;
		for (int i = 1; i <= K; i++) {
			if (N - i >= 0) {
				ans = Math.min(ans, (Math.abs(a[N] - a[N - i]) + frog2(dp, a, N - i, K)));
			}
		}
		dp[N] = ans;
		return ans;

	}

	static void sort(int[] a) {
		ArrayList<Integer> l = new ArrayList<>();
		for (int i : a)
			l.add(i);
		Collections.sort(l);
		for (int i = 0; i < a.length; i++)
			a[i] = l.get(i);
	}

	static class FastScanner {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer("");

		String next() {
			while (!st.hasMoreTokens())
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		int[] readArray(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		long nextLong() {
			return Long.parseLong(next());
		}
	}

}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz