import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    }

    static class Problem {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    }

    static class Problem {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) Problem solver = new Problem(); solver new Problem() solver.solve(0, in, out) solver.solve solver 0 in out out.close() out.close out String[] args args static class Problem {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        }

    } Problem public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        } solve {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        } int N = in.nextInt() N in.nextInt() in.nextInt in K = in.nextInt(); K in.nextInt() in.nextInt in int[] stones = new int[N]; stones new int[N] N for (int i = 0; i < N; i++)
                stones[i] = in.nextInt(); int i = 0; int i = 0; i 0 i < N i N i++ i++ i stones[i] = in.nextInt(); stones[i] = in.nextInt() stones[i] stones i in.nextInt() in.nextInt in int[] dp = new int[N]; dp new int[N] N dp[0] = 0 dp[0] dp 0 0 for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            } int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            } {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            } dp[i] = Integer.MAX_VALUE dp[i] dp i Integer.MAX_VALUE Integer Integer.MAX_VALUE for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                } int j = 1; int j = 1; j 1 j <= K && (i - j) >= 0 j <= K j K (i - j) >= 0 (i - j) i j 0 j++ j++ j {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                } {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                } int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j]; jump Math.abs(stones[i] - stones[i - j]) + dp[i - j] Math.abs(stones[i] - stones[i - j]) Math.abs Math stones[i] - stones[i - j] stones[i] stones i stones[i - j] stones i - j i j dp[i - j] dp i - j i j dp[i] = Math.min(dp[i], jump) dp[i] dp i Math.min(dp[i], jump) Math.min Math dp[i] dp i jump out.println(dp[N - 1]) out.println out dp[N - 1] dp N - 1 N 1 int testNumber testNumber InputReader in in PrintWriter out out static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    } InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } IOException e {
                    throw new RuntimeException(e);
                } throw new RuntimeException(e); new RuntimeException(e) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    }

    static class Problem {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    }

    static class Problem {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);

        Problem solver = new Problem();
        solver.solve(0, in, out);
        out.close();
    }

    static class Problem {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt(), K = in.nextInt();
            int[] stones = new int[N];
            for (int i = 0; i < N; i++)
                stones[i] = in.nextInt();

            int[] dp = new int[N];
            dp[0] = 0;

            for (int i = 1; i < N; i++) {
                dp[i] = Integer.MAX_VALUE;
                for (int j = 1; j <= K && (i - j) >= 0; j++) {
                    int jump = Math.abs(stones[i] - stones[i - j]) + dp[i - j];
                    dp[i] = Math.min(dp[i], jump);
                }
            }

            out.println(dp[N - 1]);
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
}

