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