// Original C++ solution (slower):
#include <bits/stdc++.h>

#define F first

#define S second

#define T second.first

#define C second.second

#define FIO ios_base::sync_with_stdio(0);cin.tie(0);

using namespace std;

typedef long long ll;

typedef pair<int, int> pii;

typedef pair<int,pair<int,int>> piii;



const int N= 1e5+5, L = 14, OO = 0x3f3f3f3f;

const ll M=10 ;

const double ESP = 1e-8;



int n, k;

int A[N], dp[N];

int main(){

    FIO

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

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

    cin>>n>>k;

    for(int i=0; i<n; i++)cin>>A[i];

    memset(dp, OO, sizeof dp);

    dp[0] = 0;

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

        for(int j=1; j<=k; j++){

            if(i+j<n){

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

            }

        }

    }

    cout<<dp[n-1];



}


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

#include<bits/stdc++.h>

#include<unordered_map>

using namespace std;

//<DEFINE>

void Fast() {

	ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

}

void File() {

#ifndef ONLINE_JUDGE

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

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

#endif

}

#define ll long long

#define ull unsigned long long

#define mod 1000000007

ll gcd(ll a, ll b) {

	return!b ? a : gcd(b, a % b);

}

#define fix(n) cout << fixed << setprecision(n);

#define numOfOnes(n) __builtin_popcount(n)

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

#define skip continue

#define stop(n) return cout<<n,0

#define pi  acos(-1)

#define endl "\n"

#define ceil(x,y) (x+y-1)/y

//</DEFINE>



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int n,k;

vector<int>v;

ll res[100001];

//<FUNCTIONS>

ll solve(int idx = 0) {

	if (idx == n - 1)return 0;

	if (~(res[idx]))return res[idx];

	ll mn = INT_MAX;

	for (int i = 1; i <= k; i++) {

		if (idx + i >= n)break;

		mn = min(mn, solve(idx + i) + abs(v[idx] - v[idx + i]));

	}

	return res[idx] = mn;

}

//</FUNCTIONS>		

int main() {

	Fast();

	cin >> n >> k;

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

		res[i] = -1;

	v.resize(n);

	for (int i = 0; i < n; i++)cin >> v[i];

	cout << solve() << endl;

}


// 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;





}