#include <iostream>
#include <vector>
using namespace  std;
int n, k;
int niza[100005];
int dp[100005];
int jump(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, jump(i + j) + abs(niza[i] - niza[i + j]));
        }
    }
    dp[i] = result;
    return result;
}
int main() {
    cin >> n >> k;
    for(int i = 0; i < n; i++) {
        cin >> niza[i];
        dp[i] = -1;
    }
    cout << jump(0) << endl;
}