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



using namespace std;



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

#define allr(v)				((v).rbegin()), ((v).rend())

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

#define ll long long

#define pb					push_back

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



const ll oo = 1e8;

const double pi = 3.1415926535897;





const double EPS = (1e-7);

int dcmp(double x, double y) {	return fabs(x-y) <= EPS ? 0 : x < y ? -1 : 1;	}





typedef vector<int>                vi;

typedef vector<pair<int,int>>      vii;

typedef vector<ll>                 vll;

typedef vector<double>             vd;

typedef vector< vi >               vvi;

typedef vector< vd >               vvd;

typedef vector<string>             vs;

typedef pair<int, int>             pii;



/**

    * PLEASEEE READDD PROBLEEEM CARFULLY ****

    * Always check for OVERFLOW ll vs int

    * Always check for array bounds

    * Check for function return

    * READ OUTPUT SECTION AGAIN!!!

**/



struct edge{

    int from, to, w;



    edge(){}

    edge(int x, int y, int we): from(x), to(y), w(we){}



    bool operator < (const edge &rhs) const{

        return w > rhs.w;

    }



};



const int N = 1e5 + 5, K = 100 + 5;



int dp[N];

int h[N];

int n, k = 2;



int sol(int idx) {

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



    int &ret = dp[idx];



    if(ret != -1) return ret;



    ret = 1e9 + 5;

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

        ret = min(ret, sol(idx + i) + abs(h[idx] - h[idx + i]));

    }



    return ret;

}



int main(){

    fIO



//    freopen("", "r", stdin);

//    freopen("", "w", stdout);



    memset(dp, -1, sizeof(dp));

    cin >> n >> k;



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



    cout << sol(0) << "\n";



}














// Faster C++ solution for the same problem (measured speedup: 1.388405584029952x):
#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;

}