import java.util.*;


class Main {
  public static void main(String[] args) {
    int n, k;
    Scanner sc = new Scanner(System.in);
    n = sc.nextInt();
    k = sc.nextInt();
    
    int[] h = new int[n];
    for(int i = 0; i < n; i++) {
      h[i] = sc.nextInt();
    }
    int[] dp = new int[n];
    Arrays.fill(dp, Integer.MAX_VALUE);
    dp[0] = 0;
    dp[1] = Math.abs(h[0] - h[1]);
    for(int i = 2; i < n; i++) {
      for(int j = 1; j <= k && i-j >= 0; j++) {
          dp[i] = Math.min(dp[i], dp[i-j] + Math.abs(h[i] - h[i-j]));
      }
    }
   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