#include <bits/stdc++.h>
using namespace std;

int main() {
	int n, k;
	cin>>n>>k;
	vector<int> arr(n+1, 0);
	for(int i=1;i<=n;i++){
		int element;
		cin>>element;
		arr[i]=element;
	}
	vector<int> dp(n+1,0);
	dp[1]=0;
	dp[2]=abs(arr[2]-arr[1]);
	for(int i=3;i<=n;i++){
		int answer=INT_MAX;
		for(int j=1;j<=k && i-j>=1;j++){
			//we are jumping from i-j to i
			int option=abs(arr[i]-arr[i-j]) + dp[i-j];
			answer=min(answer, option);
		}
		dp[i]=answer;
	}
	cout<<dp[n];
	return 0;
}