#include <bits/stdc++.h>
using namespace std;
void solve(){
	int n;
	cin>>n;
	int k;
	cin>>k;
	int a[n+1] =  {0};
 
	for(int i = 1; i <= n ; i++){
		cin>>a[i];
	}
 
	int dp[n+1]  = {0};
 
	dp[1] = 0;
	dp[2] = abs(a[2] - a[1]);
	// cout<<dp[1]<<" "<<dp[2]<<" ";
	for(int i=3;i<=n;i++){
		// dp[i]=min(dp[i-1]+abs(a[i]-a[i-1]),dp[i-2]+abs(a[i]-a[i-2]));
		dp[i]=INT_MAX;
		for(int j=i-1;j>=1 && (i-j)<=k;j--)
        {
            dp[i] = min(dp[i], abs(a[j] - a[i]) + dp[j]);
        }
		// cout<<dp[i]<<" ";
	}
	// cout<<"\n";
	cout<<dp[n];
 
}
int main() {
	// your code goes here
	// int tc;
	// cin>>tc;
 
	// while(tc--){
		solve();
	// }
 
	return 0;
}

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