import java.util.Scanner;

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