#include <bits/stdc++.h>
#define FOR(i,s,e) for (int i=s; i<=e; i++)
#define FOD(i,s,e) for (int i=s; i>=e; i--)
#define pb push_back
#define INF INT_MAX
#define SIZE 200000
 
using namespace std;
 
int N,K;
int h[SIZE],dp[SIZE];
 
int main() {
	cin >> N >> K;
	dp[0]=0;
	FOR(i,1,N) {
		cin >> h[i];
		dp[i]=0;
	}
	dp[2]=abs(h[2]-h[1]);
	FOR(i,3,N) {
		dp[i]=INF;
		FOR(j,1,fmin(K,i-1)) {
			dp[i]=fmin(dp[i],dp[i-j]+abs(h[i]-h[i-j]));
		}
	}
	cout << dp[N];
 
	return 0;
}
 

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