#include<bits/stdc++.h>
using namespace std;
using P = pair<int, int>;

int main() {
    int n, k;
    cin >> n >> k;
    vector<int> a(n);
    for (int i = 0; i < n; ++i)
        cin >> a[i];

    priority_queue<P> lower;
    priority_queue<P, vector<P>, greater<P>> upper;
    long long lower_sum = 0, upper_sum = 0;
    for (int i = 0; i < k; ++i) {
        upper.push(P(a[i], i));
        upper_sum += a[i];
    }
    while (lower.size() < upper.size()) {
        lower_sum += upper.top().first;
        upper_sum -= upper.top().first;
        lower.push(upper.top());
        upper.pop();
    }
    int lc = lower.size();
    int uc = upper.size();

    long long ans = 1e18;

    for (int i = k - 1; i < n; ++i) {
        if (i >= k) {
            if (P(a[i - k], i - k) > lower.top()) {
                --uc;
                upper_sum -= a[i - k];
            }
            else {
                --lc;
                lower_sum -= a[i - k];
            }
            P p = P(a[i], i);
            if (lower.top() > p) {
                ++lc;
                lower.push(p);
                lower_sum += a[i];
            }
            else {
                ++uc;
                upper.push(p);
                upper_sum += a[i];
            }
            while (lc > uc + 1) {
                if (lower.top().second <= i - k) {
                    lower.pop();
                    continue;
                }
                upper_sum += lower.top().first;
                lower_sum -= lower.top().first;
                ++uc;
                upper.push(lower.top());
                --lc;
                lower.pop();
            }
            while (lc < uc) {
                if (upper.top().second <= i - k) {
                    upper.pop();
                    continue;
                }
                lower_sum += upper.top().first;
                upper_sum -= upper.top().first;
                ++lc;
                lower.push(upper.top());
                --uc;
                upper.pop();
            }

        }
        while (lower.top().second <= i - k) {
            lower.pop();
        }
        long long m = lower.top().first;
        ans = min(ans, m * lc - lower_sum + upper_sum - m * uc);
        // cout << m * lc - lower_sum + upper_sum - m * uc << "\n";
    }
    cout << ans << "\n";
    return 0;
}