
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Scanner;
import java.util.StringTokenizer;


public class Main {
	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) throws Exception {
		int n = sc.nextInt();
		int k =sc.nextInt();
		long[]a = input(n);
		long[] dp = new long[n];
		for(int i =1 ; i < n ;i++) {
			long max = Integer.MAX_VALUE ;
			for(int j =1  ; j<=k && i-j>=0;j++ ) {
				long temp = Math.abs(a[i]-a[i-j]) + dp[i-j];
				max = Math.min(temp, max);
			}
			dp[i]=max  ;
		}
		System.out.println(dp[n-1]);
	}
	public static long[] input(int n) throws Exception {

		long[] arr = new long[n];
		for (int i = 0; i < n; i++) {
			arr[i] = sc.nextLong();
		}
		return arr;
	}

}

/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