using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Numerics;

namespace AtCoderWorkspace
{
    public class Solver
    {
        public void Solve()
        {
            var cin = new Scanner();
            var n = cin.nextInt();
            var k = cin.nextInt();
            var a = cin.ArrayInt(n);

            var dp = Enumerable.Repeat<int>(int.MaxValue, n).ToArray();
            dp[0] = 0;
            for (int i = 0; i < n; i++)
            {
                for (int j = i + 1; j <= Math.Min(k+i,n-1); j++)
                {
                    var h = Math.Abs(a[i] - a[j]) + dp[i];
                    dp[j] = Math.Min(h, dp[j]);
                }
            }

            Console.WriteLine(dp[n-1]);
        }
    }

    class DP
    {
        public static void ChMin(ref int a, int b)
        {
            long la = a;
            long lb = b;
            ChMin(ref la, lb);
        }

        public static bool ChMin(ref long a, long b)
        {
            if (a > b)
            {
                a = b;
                return true;
            }
            return false;
        }

        public static void ChMax(ref int a, int b)
        {
            long la = a;
            long lb = b;
            ChMax(ref la, lb);
        }

        public static bool ChMax(ref long a, long b)
        {
            if (a < b)
            {
                a = b;
                return true;
            }
            return false;
        }
    }

    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public int[] DPArrayInt(int N, int ex)
        {
            int[] Array = new int[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt();
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public long[] DPArrayLong(int N, int ex)
        {
            long[] Array = new long[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong();
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }

    class Program
    {
        static void Main(string[] s) => new Solver().Solve();
    }
}


Measured memory_bytes: 20064