#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
int n, k;
int arr[100005];
int dp[100005];
int frog(int i) {
    if(i >= n - 1) {
        return 0;
    }
    if(dp[i] != -1) {
        return dp[i];
    }
    int result = 2e9;
    for(int j = 1; j <= k; j++) {
        if(i + j < n) {
            result = min(result, frog(i + j) + abs(arr[i] - arr[i + j]));
        }
    }
    
    return dp[i] = result;
}
int main()
{
    cin >> n >> k;
    for(int i = 0; i < n; i++) {
        cin >> arr[i];
    }
    memset(dp, -1, sizeof dp);
    cout << frog(0) << endl;
    return 0;
}