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

using namespace std;

typedef long long ll;

typedef unsigned long long ull;

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

#define     bug(a,b)        cout<<a<<"\t"<<b<<"\n";

#define     Case(a,b)       cout<<"Case "<<a<<": "<<b<<"\n";

#define     watch(a)        cout<<fixed<<setprecision(a)

#define     lp(i,a,b)       for(int i=a;i<b;i++)

#define     Endl            "\n";

#define     tab             "\t"

#define     reset(a,b)      memset(a,b,sizeof(a));

#define     sf(a)           scanf(" %d", &a);

#define     srt(a)          sort(a.begin(),a.end());

#define     pi              2*acos(0.0)

#define     inf             INT_MAX

const int sz=1e5+9;

int n,x,arr[sz],dp[sz],k;



int clac(int i){

    if(i==n) return 0;

    if(dp[i]!=-1)return dp[i];

    int ret1=inf;

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

        ret1=min(ret1,abs(arr[i]-arr[i+j])+clac(i+j));

    }

    return dp[i]=ret1;

}



void solve(){

    cin>>n>>k;

    reset(dp,-1);

    lp(i,1,n+1)cin>>arr[i];

    cout<<clac(1)<<"\n";

}



int main(){

    //FasterIO;

    #ifndef ONLINE_JUDGE

       //freopen("1.txt","r",stdin);

    #endif

    // int t;

    //cin>>t;

    //while(t--)

        solve();

}


// Optimized solution to the same problem (faster):
#include <bits/stdc++.h>

/**

*   author: j o s e m a g o

*   date:

**/

using namespace std;

#pragma GCC optimize ("Ofast")

#define f first

#define s second

#define mp make_pair

#define lb lower_bound

#define ub upper_bound

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

#define mset(a,v) memset(a,v,sizeof(a))

#define pb push_back

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

#define rsz resize

#define ln "\n"



typedef double db;

typedef unsigned long long ull;

typedef long long ll;

typedef long double ld;

const ld PI = 2*acos(0.0);

const int MOD = 1000000007;

const int JJJ = 100009;









int main(){



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

  //freopen("input.out","w",stdout);



    ios_base::sync_with_stdio(0); cin.tie(0);



    int N,k;

    cin >> N >> k;

    vector<int>h(N+k+1);

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

        cin >> h[i];

    }

    vector<int>dp(N+k+1,INT_MAX);

    dp[0] = 0;

    for(int i = 1;i < k;i++) dp[i] = abs(h[i]-h[0]);

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

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

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

        }

    }



//    for(int i = 0;i < N;i++) cerr<<dp[i]<<" ";

    cout<<dp[N-1];









    return 0;

}


// 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;





}