import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	private static long dp[];

	private static long util(int arr[], int start, int k, int end) {

		if (start >= end - 1)
			return 0;

		if (dp[start] != 0)
			return dp[start];
		long ans = Long.MAX_VALUE;

		for (int j = 1; j <= k; j++) {

			if (start + j < end) {
				ans = Math.min(ans, Math.abs(arr[start] - arr[start + j]) + util(arr, start + j, k, end));
			}
		}
		return dp[start] = ans;

	}

	private static long util1(int arr[],int k,int end) {
		
		dp[0] = 0;
		dp[1] = Math.abs(arr[1] - arr[0]);
		
		for(int i=2; i<arr.length; i++) {
			dp[i] = Integer.MAX_VALUE;
			for(int j = i - 1;  j >= 0 && j >=i - k;  j--  ) {
			
				dp[i] = Math.min(dp[j] + Math.abs(arr[i] - arr[j]) ,dp[i] );
				
			}
		}
		return dp[end-1];
		
	}

	public static void main(String[] args) {

		FastReader sc = new FastReader();

		int n = sc.nextInt();
		int k = sc.nextInt();

		int arr[] = new int[n];

		for (int i = 0; i < n; i++) {
			arr[i] = sc.nextInt();
		}
		dp = new long[n];
		System.out.println(util1(arr, k, 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