// Original C++ solution (slower):
#define __USE_MINGW_ANSI_STDIO

#define _CRT_SECURE_NO_WARNINGS

#include <bits/stdc++.h>

#include <unordered_set>

#include <unordered_map>



using namespace std;



typedef long long ll;

typedef long long ull;

typedef pair<ll, ll> ii;



#define all(v)		((v).begin()), ((v).end())

#define sz(v)		((int)((v).size()))

#define endl		"\n"

#define fx(n)		fixed<<setprecision(n)

#define mk			make_pair	



void File()

{

#ifndef ONLINE_JUDGE

	freopen("output.txt", "w", stdout);

	freopen("input.txt", "r", stdin);

#endif

#ifdef ONLINE_JUDGE

	/*freopen("output.txt", "w", stdout);

	freopen("pyramid.in", "r", stdin);*/

#endif

}

void fast()

{

	ios::sync_with_stdio(NULL);

	cout.tie(NULL);

	cin.tie(NULL);

	//File();

}

const double pi = 2 * acos(0.0);

const ll oo = 0x3f3f3f3f;

const int MOD = 1e9 + 7;

const int nn = 1e5 + 15;

int dx[8] = { 1, -1, 0, 0, 1, -1, 1, -1 };

int dy[8] = { 0, 0, 1, -1, 1, -1, -1, 1 };



int n, k;

ll arr[nn];

ll dp[nn];

int main()

{

	fast();

	cin >> n >> k;

	for (int i = 0; i < n; i++)

		cin >> arr[i];

	fill(dp, dp + nn, oo*oo);

	dp[0] = 0;

	dp[1] = abs(arr[1] - arr[0]);

	for (int i = 2; i < n; i++)

	{

		ll mn = oo*oo;

		for (int j = 1; j <= min({ i, k }); j++)

		{

			mn = min(mn, dp[i - j] + abs(arr[i - j] - arr[i]));

		}

		dp[i] = mn;

	}

	cout << dp[n - 1] << endl;

	return 0;

}

// Optimized solution to the same problem (faster):
#define _CRT_SECURE_NO_WARNINGS

#include<bits/stdc++.h>

#define rep(i,a,n) for (int i=a;i<n;i++)

#define per(i,a,n) for (int i=n-1;i>=a;i--)

#define all(s) s.begin(),s.end()

#define sz(s) (int)s.size()

#define clr(v, d) memset(v, d, sizeof(v))

#define fi first

#define se second

#define pp push_back

#define pb pop_back

#define pi 3.141592654

#define MOD 1000000007 

#define cons1 1e12

#define cons2 1e6

using namespace std;

typedef long long ll;

typedef vector<int> vi;

typedef pair<int, int> pa;

typedef unsigned long long int ull;

typedef double long dl;

const int N = 1e5+9,oo=1e9;

int n,k;

int v[N], ans[N];

int sol(int i) {

	if (ans[i] == -1) {

		if (i == n - 1)

			ans[i] = 0;

		else {

			int x =1+ min(k, n - i - 1);

			int mx = oo;

			while (--x)

				mx = min(mx, abs(v[i] - v[i + x])+sol(i + x));

			

			ans[i] = mx;

		}



	}

	return ans[i];



}

void solve() {

	clr(ans, -1);

	cin >> n >> k;

	rep(i, 0, n)

		cin >> v[i];

	cout << sol(0) << endl;

	

}

int main() {

	ios::sync_with_stdio(0);

	cin.tie(NULL);

	cout.tie(NULL);

	int t = 1;

	//cin >> t;

	while (t--)

		solve();



#ifndef ONLINE_JUDGE

	- system("pause");

#endif



}

// Fastest known solution for this problem:
#include <iostream>

#include <array>

#include <vector>

#include <iomanip>

#include <string>

#include <cmath>

#include <array>

#include <algorithm>

#include <queue>

#include <map>

using namespace std;



typedef  pair<int,int> P;

typedef long long LL;



const LL  INF=1<<31;







int main(){

     int n,k;

     cin>>n>>k;

     int h[100000];

     for(int i=0;i<n;++i){

          cin>>h[i];

     }

     LL dp[100001];



      for(int i=0;i<n;++i){

           dp[i]=INF;

      }

            dp[0]=0;

            dp[1]=abs(h[0]-h[1]);







     for(int i=2;i<n;++i){

          dp[i]=dp[i-1]+abs(h[i-1]-h[i]);

          for(int j=2;j<=k;++j){



               if(j<=i)dp[i]=min(dp[i],dp[i-j]+abs(h[i-j]-h[i]));

          }

     }     



     cout<<dp[n-1]<<endl;





}