#include <bits/stdc++.h>
using namespace std;
 
int min_cost_to_make_jumpToN(vector<int> a, int k){
	int n = a.size();
 
	vector<int> dp(n);
	dp[0] = 0;
	dp[1] = abs(a[1] - a[0]);
 
	for (int i = 2; i < n; i++){
		int j = 1, ans = INT_MAX;
		while(j <= k && i-j >= 0){
 
			ans = min(ans, abs(a[i]-a[i-j])+dp[i-j]);
			j++;
		}
		dp[i] = ans;
 
	}
 
	return dp[n-1];
}
 
int main() {
 
	int n, k; cin >> n >> k;
	// vector<int> a = {10, 20, 5000, 10};
	vector<int> a(n);
 
	for(int &i : a){
		cin >> i;
	}
 
	cout << min_cost_to_make_jumpToN(a, k);
 
	return 0;
}

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