import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

alias sread = () => readln.chomp();
ulong MOD = 1_000_000_007;
ulong INF = 1_000_000_000_000;
alias Pair = Tuple!(long, "flag", long, "num");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

auto dp = new long[100_100];
void main()
{
    long n, k;
    scan(n, k);
    auto h = aryread();
    dp[] = INF;
    dp[0] = 0, dp[1] = abs(h[1] - h[0]);
    foreach (i; iota(2, n))
    {
        foreach (j; iota(1, min(i, k) + 1))
        {
            dp[i] = min(dp[i - j] + abs(h[i] - h[i - j]), dp[i]);
        }
    }
    dp[n - 1].writeln();
}
