#include<bits/stdc++.h>
using namespace std;
 
#define ll long long int
#define endl "\n"
 
int main(){
  int n,k;
  cin>>n>>k;
  vector<int> steps(n+1,0);
  for(int i=1;i<=n;++i){
    cin>>steps[i];
  }
  vector<int> dp(n+1,INT_MAX);
 
  dp[0]=0;
  dp[1]=0;
  for(int i=2;i<=n;++i){
    for(int j=1;j<=k;++j){
      if(i-j>=0)
      dp[i]=min(dp[i],dp[i-j]+abs(steps[i]-steps[i-j]));
    }
    // dp[i] = min((dp[i-1]+abs(steps[i]-steps[i-1])),(dp[i-2]+abs(steps[i]-steps[i-2])));
  }
  cout<<dp[n]<<endl;
 
}

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MiAxCjEwIDEwCg==

2 1
10 10