import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Main {
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }

    static int N;
    static int K;
    static int[] h;

    public static void main(String[] args) throws IOException {
        Reader sc = new Reader();
        PrintWriter out = new PrintWriter(System.out);
        N = sc.nextInt();
        K = sc.nextInt();
        h = new int[N];

        for(int i=0; i<N; ++i) {
            h[i] = sc.nextInt();
        }

        int r = jump(N, K, h);
        out.println(r);
        out.close();
    }

    public static int jump(int N, int K, int[] h) {
        int[] v = new int[N];

        K = Math.min(N-1, K);

        for(int j=1; j<N; ++j) {
            int t = Math.abs(h[j-1]-h[j]) + v[j-1];
            for(int d=2; (d<=K) && (j-d>=0); ++d) {
                t = Math.min(Math.abs(h[j-d]-h[j]) + v[j-d], t);
            }
//            boolean bContinue = true;
//            for(int d=2; d<=K && bContinue; ++d) {
//                int i = j-d;
//                if(i>=0){
//                    t = Math.min(Math.abs(h[i]-h[j]) + v[i], t);
//                }
//                else {
//                    bContinue = false;
//                }
//            }

            v[j] = t;
        }

        return v[N-1];
    }
}


Measured memory_bytes: 21716