//ssenseeeeeeeeeeeeeeeeeeeeeeeeeeeee
#include<bits/stdc++.h>
#define startt ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
typedef unsigned long long ull;
typedef long long  ll;
#define MOD 1000000007
#define MX 1000000000
#define NMAX 100005
#define MXL 1000000000000000000
#define PI 3.14159265
#define pb push_back
using namespace std;
#define sc second
#define endl '\n'
#define fr first
 
int main()
{
    int n, k;
    cin >> n >> k;
    int a[n+1];
    for(int i = 0; i < n; i++)
    {
        cin >> a[i];
    }
    int dp[10001];
    dp[0] = 0;
    for(int i = 1; i < n; i++)
    {
        dp[i] = MX;
        for(int j = i-1; j >= max(0, i-k); j--)
        {
            dp[i] = min(dp[i], dp[j]+abs(a[j]-a[i]));
        }
    }
    cout << dp[n-1] << endl;;
}