// Slower C++ solution:
#include <bits/stdc++.h>

using namespace std;



typedef long double LD;

typedef long long ll;

typedef map<int,int> mii;

typedef pair<int,int> pii;

typedef vector<pii> vpii;



#define pb              push_back

#define mp              make_pair

#define F               first

#define S               second

#define mod             1000000007

#define INF             2147483647

#define Endl            "\n"

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

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

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

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

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

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



const int MAXN = 1000005;

const int SQRTN = 1003;

const int LOGN = 22;

const double PI=acos(-1);

const int sz=1e5+9;



int strtoint(string str){

    stringstream ss(str);

    int x = 0;

    ss >> x ;

    return x ;

}

string intostr(int x){

    stringstream ss;

    ss << x;

    string str = ss.str();

    return str;

}

void rem(string &s, const string &c) {

	auto pos = s.find(c);

	if (pos == string::npos) {

		cout << -1 << endl;

		exit(0);

	}

	s.erase(0, pos + 1);

}

void println (int n){

    cout<<n<<"\n";

}

void printvec(vector <int> &a){

    for (int i=0;i<a.size();i++){

        cout<<a[i]<<" ";

    }

    cout<<"\n";

}



void printgraph(vector <int> g[],int e){

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

        cout<<i<<" --> ";

        for (int j=0;j<g[i].size();j++){

            cout<<g[i][j]<<" ";

        }

        cout<<"\n";

    }

}



void printmap (map <int,int> &mymap){

    for (auto itr = mymap.begin(); itr != mymap.end(); ++itr) {

        cout << '\t' << itr->first

             << '\t' << itr->second << '\n';

    }

    cout << "\n";

}



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





int rec (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])+rec(i+j));

    }

    return dp[i]=ret1;

}





void solve(){



    cin>>n>>k;

    reset (dp,-1);

    for (int i=1;i<=n;i++)cin>>arr[i];





    cout << rec (1) << Endl;



    //printvec(v);

}





int main(){

    //FasterIO;



    solve();

    return 0;

}

// Faster C++ solution for the same problem (measured speedup: 1.4051781257990887x):
																//  SMOKE SHISHA PLAY FIFA  // 

#include<bits/stdc++.h>

using namespace std;



typedef long long int ll;

typedef long double ld;



#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);

#define pll pair<ll,ll>

#define MP make_pair

#define ff first

#define ss second

#define PB push_back

#define mod 1000000007

#define lp(i,start,end) for(ll i=start;i<=end;i++) 

#define deb1(a) cout<<#a<<" = "<<(a)<<endl;

#define deb2(a,b) cout<<#a<<" = "<<(a)<<", "<<#b<<" = "<<(b)<<endl;

#define deb3(a,b,c) cout<<#a<<" = "<<(a)<<", "<<#b<<" = "<<(b)<<", "<<#c<<" = "<<(c)<<endl;





ll modu(ll a, ll b)

{

	ll ans =1;

	while(b>0)

	{

		if(b&1)

		ans = (ans*a)%mod;

		b/=2;

		a = (a*a)%mod;

	}

	return ans;

}



int main()

{

	fastio

	ll t=1;

	//cin >> t;

	while(t--)

	{

		ll n,k;

		cin>>n>>k;

		ll a[n+1];

		ll cost[n+1];

		lp(i,1,n){

			cin>>a[i];

			cost[i]=mod;

		}

		cost[1]=0;

		lp(i,2,n){

			for(ll j=i-1; j>= max((ll)1,i-k) ;j--){

				cost[i]=min(cost[i],cost[j]+abs(a[i]-a[j]));

			}

		}

		cout<<cost[n]<<endl;

	}

	return 0;	

}