#include <iostream>
#include<cmath>
using namespace std;
int niza[1000005];
int dp[100005];
int n;
int k;
int mini(int a,int b)
{
    int m=0;
    if(a<b)
    {
      m=a;
    }else
    {
        m=b;
    }
    return m;
}
int f(int frog_at)
{
    if(frog_at==(n-1))
    {
        return 0;
    }
    if(dp[frog_at] != -1) {
        return dp[frog_at];
    }
    int result=2e9;
    for(int i=1;i<=k;i++)
    {
       if(frog_at+i<n)
       {
           result=mini(result,f(frog_at+i)+ abs(niza[frog_at]-niza[frog_at+i]));
       }
    }
    return dp[frog_at] = result;

}
int main()
{
    cin>>n>>k;
    for(int i=0;i<n;i++)
    {
        cin>>niza[i];
        dp[i] = -1;
    }
    cout<<f(0);
    return 0;
}