//Solution By SlavicG
#include "bits/stdc++.h"
using namespace std;
 
#define ll                          long long
 
#define forn(i,n)                   for(int i=0;i<n;i++)
#define all(v)                      v.begin(), v.end()
#define rall(v)                     v.rbegin(),v.rend()
	
#define pb                          push_back
#define sz(a)                       (int)a.size()
 
#define fastio                      ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define   endl                      "\n"

int main()
{
	int n,k;
	cin >> n >> k;
    int a[n];
    int dp[n];
    forn(i,n)cin >> a[i];
    forn(i,n)dp[i] = INT_MAX;
    dp[0] = 0;
    for(int i = 0;i<n;i++)
    {
        for(int j = 1 ; j <= k;j++)
        {
            if(i + j < n)dp[i+j] = min(dp[i + j], dp[i] + max(a[i + j] , a[i]) - min(a[i + j] , a[i]));
        }
    }
    cout << dp[n-1] << endl;
}