#include <algorithm>
#include <atcoder/all>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int, int>
#define pil pair<int, ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pair<ll, ll>>
#define vvpii vector<vector<pair<int, int>>>
#define vvpll vector<vector<pair<ll, ll>>>

using mint = modint998244353;

template <typename T>
void debug(T e) {
    cerr << e << endl;
}

template <typename T>
void debug(vector<T> &v) {
    rep(i, v.size()) { cerr << v[i] << " "; }
    cerr << endl;
}

template <typename T>
void debug(vector<vector<T>> &v) {
    rep(i, v.size()) {
        rep(j, v[i].size()) { cerr << v[i][j] << " "; }
        cerr << endl;
    }
}

template <typename T>
void debug(vector<pair<T, T>> &v) {
    rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; }
}

template <typename T>
void debug(set<T> &st) {
    for (auto itr = st.begin(); itr != st.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(multiset<T> &ms) {
    for (auto itr = ms.begin(); itr != ms.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(map<T, T> &mp) {
    for (auto itr = mp.begin(); itr != mp.end(); itr++) {
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << H << " ";
    debug_out(T...);
}

multiset<ll> st1;
multiset<ll> st2;
ll val1 = 0;
ll val2 = 0;

void flatten() {
    while (st1.size() > st2.size() + 1) {
        auto ritr = st1.end();
        ritr--;
        ll val = *ritr;
        st1.erase(ritr);
        st2.insert(val);
        val1 -= val;
        val2 += val;
    }
    while (st1.size() < st2.size()) {
        auto itr = st2.begin();
        ll val = *itr;
        st2.erase(itr);
        st1.insert(val);
        val2 -= val;
        val1 += val;
    }
}

void st_push(ll x) {
    if (st2.size() == 0) {
        st1.insert(x);
        val1 += x;
    } else {
        auto itr = st2.begin();
        ll val = *itr;
        if (x >= val) {
            st2.insert(x);
            val2 += x;
        } else {
            st1.insert(x);
            val1 += x;
        }
    }
    flatten();
}

void st_pop(ll x) {
    if (st1.find(x) == st1.end()) {
        st2.erase(st2.find(x));
        val2 -= x;
    } else {
        st1.erase(st1.find(x));
        val1 -= x;
    }
    flatten();
}

ll calc_ans() {
    ll center = *(st1.rbegin());
    ll size_1 = st1.size();
    ll size_2 = st2.size();
    ll ret = (val2 - size_2 * center) + (size_1 * center - val1);
    return ret;
}

int main() {
    ll N, K;
    cin >> N >> K;
    vector<ll> A(N);
    for (ll i = 0; i < N; i++) {
        cin >> A[i];
    }
    for (ll i = 0; i < K; i++) {
        st_push(A[i]);
    }
    ll ans = calc_ans();
    for (ll i = K; i < N; i++) {
        st_push(A[i]);
        st_pop(A[i - K]);
        ans = min(ans, calc_ans());
    }
    cout << ans << endl;
}