/*input
10 4
40 10 20 70 80 10 20 70 80 60
*/
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.PriorityQueue;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author masterbios
 */
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);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, in, out);
        out.close();
    }

    static class CLinovaAndKingdom {
       

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        }

        public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        }

        public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        }

    }

    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.hasMoreElements()) {
                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.util.PriorityQueue; PriorityQueue java.util import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util import java.util.Arrays; Arrays java.util import java.util.StringTokenizer; StringTokenizer java.util import java.io.BufferedReader; BufferedReader java.io import java.io.InputStream; InputStream java.io 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);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, in, out);
        out.close();
    }

    static class CLinovaAndKingdom {
       

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        }

        public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        }

        public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        }

    }

    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.hasMoreElements()) {
                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);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, 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) CLinovaAndKingdom solver = new CLinovaAndKingdom(); solver new CLinovaAndKingdom() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class CLinovaAndKingdom {
       

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        }

        public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        }

        public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        }

    } CLinovaAndKingdom public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        } solve {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            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 a[] = new int[n]; a new int[n] n int dp[] = new int[n]; dp new int[n] n for (int i = 0; i < n; i++) a[i] = in.nextInt(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = in.nextInt(); a[i] = in.nextInt() a[i] a i in.nextInt() in.nextInt in Arrays.fill(dp, (int) 1e9) Arrays.fill Arrays dp (int) 1e9 dp[0] = 0 dp[0] dp 0 0 for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            } int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            } {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            } for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                } int j = 1; int j = 1; j 1 j <= k j k j++ j++ j {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                } {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                } if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    } i >= j i j {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    } dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j])) dp[i] dp i min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j])) min dp[i] dp i dp[i - j] + Math.abs(a[i] - a[i - j]) dp[i - j] dp i - j i j Math.abs(a[i] - a[i - j]) Math.abs Math a[i] - a[i - j] a[i] a i a[i - j] a i - j i j 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 public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        } max {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        } int max = Integer.MIN_VALUE; max Integer.MIN_VALUE Integer Integer.MIN_VALUE for (int i : a) max = Math.max(max, i); int i a max = Math.max(max, i); max = Math.max(max, i) max Math.max(max, i) Math.max Math max i return max; max int ...a a public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        } min {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        } int min = Integer.MAX_VALUE; min Integer.MAX_VALUE Integer Integer.MAX_VALUE for (int i : a) min = Math.min(min, i); int i a min = Math.min(min, i); min = Math.min(min, i) min Math.min(min, i) Math.min Math min i return min; min int ...a a 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.hasMoreElements()) {
                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.hasMoreElements()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreElements()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreElements()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreElements() tokenizer == null tokenizer null !tokenizer.hasMoreElements() tokenizer.hasMoreElements() tokenizer.hasMoreElements 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);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, in, out);
        out.close();
    }

    static class CLinovaAndKingdom {
       

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        }

        public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        }

        public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        }

    }

    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.hasMoreElements()) {
                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);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, in, out);
        out.close();
    }

    static class CLinovaAndKingdom {
       

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        }

        public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        }

        public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        }

    }

    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.hasMoreElements()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
} Main
/*input
10 4
40 10 20 70 80 10 20 70 80 60
*/
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.PriorityQueue;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author masterbios
 */
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);
        CLinovaAndKingdom solver = new CLinovaAndKingdom();
        solver.solve(1, in, out);
        out.close();
    }

    static class CLinovaAndKingdom {
       

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++) a[i] = in.nextInt();
            Arrays.fill(dp, (int) 1e9);
            dp[0] = 0;
            for (int i = 1; i < n; i++) {
                for (int j = 1; j <= k; j++) {
                    if (i >= j) {
                        dp[i] = min(dp[i], dp[i - j] + Math.abs(a[i] - a[i - j]));
                    }
                }
            }
            out.println(dp[n - 1]);

        }

        public int max(int ...a) {
            int max = Integer.MIN_VALUE;
            for (int i : a) max = Math.max(max, i);
            return max;
        }

        public int min(int ...a) {
            int min = Integer.MAX_VALUE;
            for (int i : a) min = Math.min(min, i);
            return min;
        }

    }

    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.hasMoreElements()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
}

