/*
    Author: Anthony Ngene
    Created: 09/08/2020 - 22:40
*/

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

public class Main {
    // That which does not kill us makes us stronger. - Friedrich Nietzsche
    public static void main(String[] args) throws IOException {
        in = new FastScanner();

        int n = in.intNext();
        long k = in.longNext();
        long[] arr = in.nextLongArray(n);
        long[] dp = new long[n];
        Arrays.fill(dp, e97);
        dp[0] = 0;
        for (int i = 1; i < n; i++) {
            for (int j = 1; j < k + 1; j++)
                if (i - j >= 0) dp[i] = min(dp[i], abs(dp[i - j] + abs(arr[i] - arr[i - j])));
        }
        out.println(dp[n - 1]);

        out.close();
    }


    // Generated Code Below:
    private static final FastWriter out = new FastWriter();
    private static FastScanner in;
    static ArrayList<Integer>[] adj;
    private static long e97 = (long)1e9 + 7;
    static class FastWriter {
        private static final int IO_BUFFERS = 128 * 1024;
        private final StringBuilder out;
        public FastWriter() { out = new StringBuilder(IO_BUFFERS); }
        public FastWriter p(Object object) { out.append(object); return this; }
        public FastWriter p(String format, Object... args) { out.append(String.format(format, args)); return this; }
        public FastWriter pp(Object... args) { for (Object ob : args) { out.append(ob).append(" ");  } out.append("\n"); return this; }
        public void println(long[] arr) { out.append(Arrays.toString(arr)).append("\n"); }
        public void println(int[] arr) { out.append(Arrays.toString(arr)).append("\n"); }
        public void println(char[] arr) { out.append(Arrays.toString(arr)).append("\n"); }
        public void println(float[] arr) { out.append(Arrays.toString(arr)).append("\n"); }
        public void println(boolean[] arr) { out.append(Arrays.toString(arr)).append("\n"); }
        public <T>void println(T[] arr) { out.append(Arrays.toString(arr)).append("\n"); }
        public void println(long[][] arr) {  for (long[] row: arr) out.append(Arrays.toString(row)).append(" "); out.append("\n");  }
        public void println(int[][] arr) {  for (int[] row: arr) out.append(Arrays.toString(row)).append(" "); out.append("\n");  }
        public void println(char[][] arr) {  for (char[] row: arr) out.append(Arrays.toString(row)).append(" "); out.append("\n");  }
        public void println(float[][] arr) {  for (float[] row: arr) out.append(Arrays.toString(row)).append(" "); out.append("\n");  }
        public <T>void println(T[][] arr) {  for (T[] row: arr) out.append(Arrays.toString(row)).append(" "); out.append("\n");  }
        public FastWriter println(Object object) { out.append(object).append("\n"); return this; }
        public void toFile(String fileName) throws IOException {
            BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
            writer.write(out.toString());
            writer.close();
        }
        public void close() throws IOException { System.out.print(out); }
    }
    static class FastScanner {
        private InputStream sin = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        public FastScanner(){}
        public FastScanner(String filename) throws FileNotFoundException {
            File file = new File(filename);
            sin = new FileInputStream(file);
        }
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = sin.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long longNext() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b) || b == ':'){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int intNext() {
            long nl = longNext();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public double doubleNext() { return Double.parseDouble(next());}
        public long[] nextLongArray(final int n){
            final long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = longNext();
            return a;
        }
        public int[] nextIntArray(final int n){
            final int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = intNext();
            return a;
        }
        public ArrayList<Integer>[] getAdj(int n) {
            ArrayList<Integer>[] adj = new ArrayList[n + 1];
            for (int i = 1; i <= n; i++) adj[i] = new ArrayList<>();
            return adj;
        }
        public ArrayList<Integer>[] adjacencyList(int n, int m) throws IOException {
            adj = getAdj(n);
            for (int i = 0; i < m; i++) {
                int a = intNext(), b = intNext();
                adj[a].add(b);
                adj[b].add(a);
            }
            return adj;
        }
    }
    private static long abs(long a){    return (a>=0) ? a: -a;  }
    private static long min(long... ins){ long min = ins[0]; for(int i=1; i<ins.length; i++){ if(ins[i] < min) min = ins[i]; } return min; }
}


Measured memory_bytes: 45604