#include <bits/stdc++.h>

using namespace std;

using ll = long long;

//引数unzipには圧縮前のvectorを入れる
int compress(vector<ll>& unzip, map<ll, int>& zip) {
    sort(unzip.begin(), unzip.end());
    unzip.erase(unique(unzip.begin(), unzip.end()), unzip.end());
    for (int i = 0; i < unzip.size(); i++) {
        zip[unzip[i]] = i;
    }
    return unzip.size();
}

//1-indexであることに注意
template <typename T>
struct BIT {
    int n;
    vector<T> data;

    BIT(int n) : n(n), data(n + 1, 0) {}

    T sum(int i) {
        T s = 0;
        while (i > 0) {
            s += data[i];
            i -= i & -i;
        }
        return s;
    }

    void add(int i, T x) {
        while (i <= n) {
            data[i] += x;
            i += i & -i;
        }
    }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n, k;
    cin >> n >> k;
    vector<ll> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];

    vector<ll> unzip(a);
    map<ll, int> zip;
    compress(unzip, zip);
    BIT<int> b(unzip.size());
    BIT<ll> b2(unzip.size());

    ll ans = 1000000000000000LL;
    for (int i = 0; i < n; i++) {
        b.add(zip[a[i]] + 1, 1);
        b2.add(zip[a[i]] + 1, a[i]);
        if (i < k - 1) continue;
        if (i >= k) {
            b.add(zip[a[i - k]] + 1, -1);
            b2.add(zip[a[i - k]] + 1, -a[i - k]);
        }
        int ok = (int)unzip.size() - 1, ng = -1;
        while (ok - ng > 1) {
            int mid = (ok + ng) / 2;
            if (b.sum(mid + 1) >= (k + 1) / 2) ok = mid;
            else ng = mid;
        }
        ll hoge = b2.sum(unzip.size()) - b2.sum(ok + 1);
        ll foo = b.sum(unzip.size()) - b.sum(ok + 1);
        ll tmp = hoge - foo * unzip[ok];
        hoge = b2.sum(ok);
        foo = b.sum(ok);
        tmp += foo * unzip[ok] - hoge;
        ans = min(ans, tmp);
        //cout << unzip[ok] << endl;
    }
    cout << ans << endl;
    return 0;
}