#include <bits/stdc++.h>
using namespace std;
/// Luu y code tham khao dung [0, n) thay vi [1, n]
void minimize(int &a, int b) { a = min(a, b); }
int main()
{
    int n, k;
    cin >> n >> k;
 
    vector<int> a(n);
    for (int &x : a) cin >> x;
 
    vector<int> dp(n, 0);
    for (int i = 1; i < n; ++i)
    {
        dp[i] = dp[i - 1] + abs(a[i] - a[i - 1]);
        for (int j = i - 2; j >= max(0, i - k); --j)
            minimize(dp[i], dp[j] + abs(a[i] - a[j]));
    }
 
    cout << dp.back();
    return 0;
}

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