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

#include <algorithm>

#include <iostream>

#include <iomanip>

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <cstring>

#include <vector>

#include <string>

#include <climits>

#include <map>

#include <set>

#include <stack>

#include <queue>

#include <deque>

#include <stdio.h>

//#define int long long

using namespace std;

#define loop(n) for(int i=0;i<n;i++)

#define endl '\n'

#define OnlineJudgec

#define F first

#define S second

#define  precision(n)  cout << fixed << setprecision(n)

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

typedef long long ll;

typedef vector<int> vi;

void init()

{

    cin.tie(0);

    cin.sync_with_stdio(0);

    cout.tie(0);

    #ifdef OnlineJudge

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

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

    #endif

}

ll S(ll x){ll s = 0;while(x){s += x % 10;x /= 10;}return s;} /// sum of digits.

ll powe(ll a , ll n){if(n == 1)return a;return a * powe(a ,n-1);}

ll com(int n,int m){ll z = 1;for(int i = 0; i < m;i++){z = z * ( n - i) / (i + 1) ;}return z;}

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

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

int dr[] = {0,0,0,1,1,1,-1,-1,-1};

int dc[] ={-1,0,1,-1,0,1,-1,0,1};

/// <<------------------------------------------------------------------------------>>

const int mx = 100009;

int n , k;

int arr[mx];

int dp[mx];

int solve(int idx)

{

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

    int &rst = dp[idx];

    if(~rst) return rst;

    int choice = 1e9 , ans = 1e9;

    for(int i = idx + 1,cnt = 0 ;cnt < k && i < n;i++,cnt++)

    {

        choice  = solve(i) + abs(arr[idx] - arr[i]);

        ans     = min(choice , ans);

    }

    return rst = ans;

}

/// <<------------------------------------------------------------------------------>>

int main()

{

    init();

    cin >> n >> k;

    loop(n) cin >> arr[i];

    clr(dp,-1);

    cout<<solve(0);

}


// Optimized solution to the same problem (faster):
#include<cstdio>

#include<algorithm>

using namespace std;



#define ll long long 



#define file_io 0



ll i,t,j;

ll n,k,h[100005],dp[100005];



int main(){

	if (file_io){

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

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

	}

	

	scanf("%lld%lld",&n,&k);

	

	for (i=1; i<=n; ++i){

		scanf("%lld",&h[i]);

	}

	

	dp[1]=0;

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

		dp[i]=2e9;

		for (t=max(1ll,i-k); t<i; ++t){

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

		}

	}

	

	printf("%lld\n",dp[n]);

	

	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;





}