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

class Main {

    // Generated by 1.1.7.1 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
    public static void main(String[] args) throws Exception {
        final Scanner sc = new Scanner(System.in);
        long N;
        N = sc.nextLong();
        long K;
        K = sc.nextLong();
        long[] h = new long[(int)(N)];
        for(int i = 0 ; i < N ; i++){
                h[i] = sc.nextLong();
        }
        solve(N, K, h);
    }

    static void solve(long N, long K, long[] h){
        long[] dp = new long[(int)(N+1)];
        
        for (int i = 2; i <= N; i++){
            long tmp = Integer.MAX_VALUE;
            for (int j = 1; j <= K; j++){
                if (i - j - 1 >= 0){
                    tmp = Math.min(tmp, dp[i-j] + Math.abs(h[i-1] -h[i-j-1]));
                }
            }
            dp[i] = tmp;
        }
        System.out.print(dp[(int)(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