import java.util.*;
import java.io.*;
import java.util.stream.Collectors;

public class Main {
    public static final long MOD = 1000000007;
    public static final int INF = 1 << 15;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    }

    private static void print(Object o) {
        System.out.println(o.toString());
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static class Pair {
        private int key;
        private int value;

        public Pair(int key, int value){
            this.key=key;
            this.value=value;
        }

        public int getValue(){
            return this.value;
        }

        public int getKey(){
            return this.key;
        }

        public void setValue(int value){
            this.value = value;
        }
    }
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.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 nextLong() {
        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)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
} import java.util.*; util.* java import java.io.*; io.* java import java.util.stream.Collectors; Collectors java.util.stream public class Main {
    public static final long MOD = 1000000007;
    public static final int INF = 1 << 15;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    }

    private static void print(Object o) {
        System.out.println(o.toString());
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static class Pair {
        private int key;
        private int value;

        public Pair(int key, int value){
            this.key=key;
            this.value=value;
        }

        public int getValue(){
            return this.value;
        }

        public int getKey(){
            return this.key;
        }

        public void setValue(int value){
            this.value = value;
        }
    }
} Main public static final long MOD = 1000000007; MOD 1000000007 public static final int INF = 1 << 15; INF 1 << 15 1 15 public static void main(String[] args) {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    } main {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    } FastScanner sc = new FastScanner(); sc new FastScanner() PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) Integer i i j j k k n=0 n 0 m=0 m 0 h=0 h 0 w=0; w 0 long a=0 a 0 b=0 b 0 c=0 c 0 x=0 x 0 y=0 y 0 z=0 z 0 ans=0; ans 0 List<Integer> l = new ArrayList<>(); l new ArrayList<>() List<String> s = new ArrayList<>(); s new ArrayList<>() List<Pair> p = new ArrayList<>(); p new ArrayList<>() List<List<Integer>> ll = new ArrayList<>(); ll new ArrayList<>() Set<String> st = new HashSet<>(); st new HashSet<>() n = sc.nextInt() n sc.nextInt() sc.nextInt sc k = sc.nextInt() k sc.nextInt() sc.nextInt sc int[] field = new int[n]; field new int[n] n for(i=0;i<n;i++)
            field[i] = sc.nextInt(); i=0; i=0 i 0 i<n i n i++ i++ i field[i] = sc.nextInt(); field[i] = sc.nextInt() field[i] field i sc.nextInt() sc.nextInt sc int[] dp = new int[n+k+1]; dp new int[n+k+1] n+k+1 n+k+1 n k 1 for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE; i=0; i=0 i 0 i<n i n i++ i++ i dp[i]=Integer.MAX_VALUE; dp[i]=Integer.MAX_VALUE dp[i] dp i Integer.MAX_VALUE Integer Integer.MAX_VALUE dp[0] = 0 dp[0] dp 0 0 for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        } i=0; i=0 i 0 i<n-1 i n-1 n 1 i++ i++ i {
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        } {
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        } for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            } j=i+1; j=i+1 j i+1 i 1 j<=Math.min(n-1,i+k) j Math.min(n-1,i+k) Math.min Math n-1 n 1 i+k i k j++ j++ j {
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            } {
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            } dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j])) dp[j] dp j Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j])) Math.min Math dp[j] dp j dp[i] + Math.abs(field[i]-field[j]) dp[i] dp i Math.abs(field[i]-field[j]) Math.abs Math field[i]-field[j] field[i] field i field[j] field j print(dp[n-1]) print dp[n-1] dp n-1 n 1 String[] args args private static void print(Object o) {
        System.out.println(o.toString());
    } print {
        System.out.println(o.toString());
    } System.out.println(o.toString()) System.out.println System.out System System.out o.toString() o.toString o Object o o private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    } lcm {
        return m * n / gcd(m, n);
    } return m * n / gcd(m, n); m * n / gcd(m, n) m * n m n gcd(m, n) gcd m n long m m long n n private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    } gcd {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    } if(m < n) return gcd(n, m); m < n m n return gcd(n, m); gcd(n, m) gcd n m if(n == 0) return m; n == 0 n 0 return m; m return gcd(n, m % n); gcd(n, m % n) gcd n m % n m n long m m long n n private static class Pair {
        private int key;
        private int value;

        public Pair(int key, int value){
            this.key=key;
            this.value=value;
        }

        public int getValue(){
            return this.value;
        }

        public int getKey(){
            return this.key;
        }

        public void setValue(int value){
            this.value = value;
        }
    } Pair private int key; key private int value; value public Pair(int key, int value){
            this.key=key;
            this.value=value;
        } Pair {
            this.key=key;
            this.value=value;
        } this.key=key this.key this this.key key this.value=value this.value this this.value value int key key int value value public int getValue(){
            return this.value;
        } getValue {
            return this.value;
        } return this.value; this.value this this.value public int getKey(){
            return this.key;
        } getKey {
            return this.key;
        } return this.key; this.key this this.key public void setValue(int value){
            this.value = value;
        } setValue {
            this.value = value;
        } this.value = value this.value this this.value value int value value class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.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 nextLong() {
        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)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
} FastScanner private final InputStream in = System.in; in System.in System System.in private final byte[] buffer = new byte[1024]; buffer new byte[1024] 1024 private int ptr = 0; ptr 0 private int buflen = 0; buflen 0 private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    } hasNextByte {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    } if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        } ptr < buflen ptr buflen {
            return true;
        } return true; true {
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        } ptr = 0 ptr 0 try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                buflen = in.read(buffer);
            } buflen = in.read(buffer) buflen in.read(buffer) in.read in buffer if (buflen <= 0) {
                return false;
            } buflen <= 0 buflen 0 {
                return false;
            } return false; false return true; true private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} readByte { if (hasNextByte()) return buffer[ptr++]; else return -1;} if (hasNextByte()) return buffer[ptr++]; else return -1; hasNextByte() hasNextByte return buffer[ptr++]; buffer[ptr++] buffer ptr++ ptr return -1; -1 1 private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} isPrintableChar { return 33 <= c && c <= 126;} return 33 <= c && c <= 126; 33 <= c && c <= 126 33 <= c 33 c c <= 126 c 126 int c c public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} hasNext { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; hasNextByte() && !isPrintableChar(buffer[ptr]) hasNextByte() hasNextByte !isPrintableChar(buffer[ptr]) isPrintableChar(buffer[ptr]) isPrintableChar buffer[ptr] buffer ptr ptr++ ptr return hasNextByte(); hasNextByte() 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();
    } next {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() StringBuilder sb = new StringBuilder(); sb new StringBuilder() int b = readByte(); b readByte() readByte while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        } isPrintableChar(b) isPrintableChar b {
            sb.appendCodePoint(b);
            b = readByte();
        } sb.appendCodePoint(b) sb.appendCodePoint sb b b = readByte() b readByte() readByte return sb.toString(); sb.toString() sb.toString sb public long nextLong() {
        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)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    } nextLong {
        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)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() long n = 0; n 0 boolean minus = false; minus false int b = readByte(); b readByte() readByte if (b == '-') {
            minus = true;
            b = readByte();
        } b == '-' b '-' {
            minus = true;
            b = readByte();
        } minus = true minus true b = readByte() b readByte() readByte if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        } b < '0' || '9' < b b < '0' b '0' '9' < b '9' b {
            throw new NumberFormatException();
        } throw new NumberFormatException(); new NumberFormatException() while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        } true {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        } if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            } '0' <= b && b <= '9' '0' <= b '0' b b <= '9' b '9' {
                n *= 10;
                n += b - '0';
            } n *= 10 n 10 n += b - '0' n b - '0' b '0' if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            } b == -1 || !isPrintableChar(b) b == -1 b -1 1 !isPrintableChar(b) isPrintableChar(b) isPrintableChar b {
                return minus ? -n : n;
            } return minus ? -n : n; minus ? -n : n minus -n n n {
                throw new NumberFormatException();
            } throw new NumberFormatException(); new NumberFormatException() b = readByte() b readByte() readByte public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    } nextInt {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    } long nl = nextLong(); nl nextLong() nextLong if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException(); nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE nl < Integer.MIN_VALUE nl Integer.MIN_VALUE Integer Integer.MIN_VALUE nl > Integer.MAX_VALUE nl Integer.MAX_VALUE Integer Integer.MAX_VALUE throw new NumberFormatException(); new NumberFormatException() return (int) nl; (int) nl public double nextDouble() { return Double.parseDouble(next());} nextDouble { return Double.parseDouble(next());} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public class Main {
    public static final long MOD = 1000000007;
    public static final int INF = 1 << 15;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    }

    private static void print(Object o) {
        System.out.println(o.toString());
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static class Pair {
        private int key;
        private int value;

        public Pair(int key, int value){
            this.key=key;
            this.value=value;
        }

        public int getValue(){
            return this.value;
        }

        public int getKey(){
            return this.key;
        }

        public void setValue(int value){
            this.value = value;
        }
    }
} public class Main {
    public static final long MOD = 1000000007;
    public static final int INF = 1 << 15;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    }

    private static void print(Object o) {
        System.out.println(o.toString());
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static class Pair {
        private int key;
        private int value;

        public Pair(int key, int value){
            this.key=key;
            this.value=value;
        }

        public int getValue(){
            return this.value;
        }

        public int getKey(){
            return this.key;
        }

        public void setValue(int value){
            this.value = value;
        }
    }
} Main
import java.util.*;
import java.io.*;
import java.util.stream.Collectors;

public class Main {
    public static final long MOD = 1000000007;
    public static final int INF = 1 << 15;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        Integer i,j,k,n=0,m=0,h=0,w=0;
        long a=0,b=0,c=0,x=0,y=0,z=0,ans=0;
        List<Integer> l = new ArrayList<>();
        List<String> s = new ArrayList<>();
        List<Pair> p = new ArrayList<>();
        List<List<Integer>> ll = new ArrayList<>();
        Set<String> st = new HashSet<>();

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

        int[] field = new int[n];

        for(i=0;i<n;i++)
            field[i] = sc.nextInt();

        int[] dp = new int[n+k+1];

        for(i=0;i<n;i++)
            dp[i]=Integer.MAX_VALUE;

        dp[0] = 0;
        for(i=0;i<n-1;i++){
            for(j=i+1;j<=Math.min(n-1,i+k);j++){
                dp[j]=Math.min(dp[j],dp[i] + Math.abs(field[i]-field[j]));
            }
        }

        print(dp[n-1]);
    }

    private static void print(Object o) {
        System.out.println(o.toString());
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static class Pair {
        private int key;
        private int value;

        public Pair(int key, int value){
            this.key=key;
            this.value=value;
        }

        public int getValue(){
            return this.value;
        }

        public int getKey(){
            return this.key;
        }

        public void setValue(int value){
            this.value = value;
        }
    }
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.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 nextLong() {
        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)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
}
