#define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define MT make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define RT return
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;

template<class Val>
struct BinaryIndexedTree {
    int n;
    vector<Val> t;
    BinaryIndexedTree() {}
    BinaryIndexedTree(int _n) :n(_n + 1), t(_n + 1) {}
    void add(int k, Val val) {
        k++;
        while (k < n) {
            t[k] += val;
            k += (k&-k);
        }
    }
    void set(int k, Val val) {
        add(k, -sum(k, k + 1));
        add(k, val);
    }
    Val sum(int k) {
        Val r = 0;
        while (k > 0) {
            r += t[k];
            k -= (k&-k);
        }
        return r;
    }
    Val sum(int l, int r) {
        return sum(r) - sum(l);
    }
};

template<class Val>
vector<Val> compress(vector<Val> &v) {
    vector<Val> a = v;
    sort(all(a));
    a.erase(unique(all(a)), a.end());
    each(b, v)b = (int)(lower_bound(all(a), b) - a.begin());
    return a;
}

void solve() {
    int N, K;
    cin >> N >> K;
    vi A(N);
    rep(i, N)cin >> A[i];
    auto B = compress(A);

    int M = sz(B);
    BinaryIndexedTree<ll> cnt(M), sum(M);
    ll ans = LLONG_MAX;

    rep(i, N) {
        cnt.add(A[i], 1);
        sum.add(A[i], B[A[i]]);
        if (i >= K) {
            cnt.add(A[i-K], -1);
            sum.add(A[i-K], -B[A[i-K]]);
        }

        if (i >= K - 1) {
            // 中央値を求める
            int l = 0, r = M;
            while (r - l > 1) {
                int m = (l + r) / 2;
                ll num = cnt.sum(0, m);
                if (num >= (K + 1) / 2) {
                    r = m;
                } else {
                    l = m;
                }
            }
            // 中央値はB[A[l]]
            ll med = B[l];
            ll val = (sum.sum(l, M) - cnt.sum(l, M)*med)
                + (cnt.sum(l)*med - sum.sum(l));
            smin(ans, val);
        }
    }

    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);
    solve();
    return 0;
}