import java.util.Arrays;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
	Scanner scn =new Scanner(System.in);
	int n = scn.nextInt();
	int k = scn.nextInt();
	int[]h = new int[n];
	for(int i=0;i<n;i++)
	{
		h[i]=scn.nextInt();
	}
	int[]dp=new int[n];
	Arrays.fill(dp, Integer.MAX_VALUE);
	dp[0]=0;
	for(int i=0;i<n;i++)
	{
		for(int j=i+1;j<=i+k;j++)
		{
			if(j<n&&dp[i]!=Integer.MAX_VALUE)
			{
				dp[j]=Math.min(dp[j], Math.abs(h[j]-h[i])+dp[i]);
			}
		}
	}
	System.out.println(dp[n-1]);
}
}
/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