import java.util.*;
import java.io.*;

public class Main {
  
   public static void main(String[]abc){
      Main ans = new Main();
      int sol = ans.solve();
      System.out.println(sol);
   }
  
   private int solve() {
      Scanner sc = new Scanner(System.in);
      int N = sc.nextInt();
      int K = sc.nextInt();
      int [] array = new int[N+1];
      for(int i=1;i<=N;i++) {
         array[i] = sc.nextInt();        
      }
      int [] dp = new int[N+1];
      Arrays.fill(dp, Integer.MAX_VALUE);
      dp[1]=0;
      dp[0]=0;
      for(int i=2;i<=N;i++){
         for(int j=i-1;j>=1 && i-j<=K;j--){
            dp[i] = Math.min(dp[j]+ Math.abs(array[j]-array[i]), dp[i]);
         }
      }
	//System.out.println(Arrays.toString(dp));
     return dp[N];
      
      
   }
}
/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