import java.util.*;

public class Main
{
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int k = sc.nextInt();
		int[] arr = new int[n];
		for(int i=0;i<n;i++)
		{
			arr[i] = sc.nextInt();
		}

		int[] dp = new int[n];
		dp[0] = 0;
		for(int i=1;i<n;i++)
		{
			int min = Integer.MAX_VALUE;
			for(int j=i-1;j>=Math.max(0,i-k);j--)
			{
				min = Math.min(min,dp[j]+Math.abs(arr[j]-arr[i]));
			}

			dp[i] = min;
		}

		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