import java.util.Scanner;

class Main {

	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		int N = sc.nextInt(),i, h[] = new int[N],K=sc.nextInt();
		for(i=0;i<N;i++)h[i]=sc.nextInt();
		int dp[]=new int[N+1];
		dp[0]=0;
		for(i=1;i<N;i++) {
			dp[i]=dp[i-1]+Math.abs(h[i]-h[i-1]);
			for(int k=1;k<=Math.min(K, i);k++) {
				dp[i]=Math.min(dp[i-k]+Math.abs(h[i]-h[i-k]), 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