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

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MTAgNAo0MCAxMCAyMCA3MCA4MCAxMCAyMCA3MCA4MCA2MAo=

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