// Slower C++ solution:
//#pragma GCC target ("avx2,sse2")

//#pragma GCC optimization ("Ofast")

//#pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>

#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;



#define ordered_set tree <pair <ll, int>, null_type, less <pair <ll, int> >, rb_tree_tag, tree_order_statistics_node_update>

#define ll long long

#define ull unsigned long long

#define db long double

#define pb push_back

#define pf push_front

#define ppb pop_back

#define ppf pop_front

#define fi first

#define se second

#define mp make_pair

#define up_b upper_bound

#define low_b lower_bound

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

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

#define endl "\n"



#define left fsdsdfoisf

#define sum dpsdfioppsf

#define assign xcvjlkdjfio

#define trie fksdfkjkfnjuiv

#define next sidlfjsfkl

#define merge sdfksdkfsldf



#define int long long



using namespace std;



void dout() {

    cerr << endl;

}

template <typename Head, typename... Tail>

void dout(Head H, Tail... T) {

    cerr << H << ' ';

    dout(T...);

}



//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef pair <int, int> pii;



const int N = 1e5 + 7, inf = 1e18;

int n, k, h[N], dp[N];



void solve(int tc) {

    // check for (int i = 0; i < n; j++)

    cin >> n >> k;

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

        cin >> h[i];

    }

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

        dp[i] = inf;

    }

    dp[1] = 0;

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

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

            if (i - j < 1) {

                break;

            }

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

        }

    }

    cout << dp[n];

}



signed main() {

    ios_base::sync_with_stdio(false);

    cin.tie(NULL);

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

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

    int tc = 1;

//    cin >> tc;

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

        solve(i);

//        cleanup();

    }

}


// Faster C++ solution for the same problem (measured speedup: 1.788343912320496x):
#include <bits/stdc++.h>



#define Solved int main()

#define pb push_back

#define mp make_pair

#define F first

#define S second

#define SpeedForce ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)

#define forn(i, n) for(int i = 1; i <= n; i++)

#define rep(i, x, y) for(int i = x; i <= y; i++)

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

#define pii pair<int, int>

#define ll long long

#define ull unsigned long long

#define ld long double

#define mii map<int, int>

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

using namespace std;



inline ll bip(ll x,ll n,ll mod){ll res=1;while(n){if(n&1){res=(res*x)%mod;}x=(x*x)%mod;n>>=1;}return res;}



const int maxn = 1e9;

const ll inf = 1e18;

const int mod = 998244353;

//const int mod = 1e9 + 7;

const int N = 1e5 + 10;



int n, k;

ll a[N];

ll dp[N];



void solve() {

    cin >> n >> k;



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

        cin >> a[i];



    dp[2] = abs(a[2] - a[1]);

    for (int i = 3; i <= n; i++) {

        dp[i] = inf;

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

            if (i > j) dp[i] = min(dp[i], dp[i - j] + abs(a[i] - a[i - j]));

        }

    }

    cout << dp[n];

}



Solved {

    SpeedForce;

	int tt = 1;

    //cin >> tt;

	while (tt--) {

		solve();

		cout << '\n';

	}



}