#include <bits/stdc++.h>
using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vector<T>>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
constexpr char ln = '\n';
template <class Container> inline int SZ(const Container& v) { return int(v.size()); }
template <class T> inline void UNIQUE(vector<T>& v) { v.erase(unique(v.begin(), v.end()), v.end()); }
template <class T1, class T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; }
template <class T1, class T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; }
inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); }
inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); }
inline int popcount(ull x) { return __builtin_popcountll(x); }
inline int kthbit(ull x, int k) { return (x >> k) & 1; }
inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; }
const string YESNO[2] = {"NO", "YES"};
const string YesNo[2] = {"No", "Yes"};
inline void YES(bool t = true) { cout << YESNO[t] << "\n"; }
inline void Yes(bool t = true) { cout << YesNo[t] << "\n"; }
template <class T> inline void drop(T x) { cout << x << "\n"; exit(0); }
inline void print() { cout << "\n"; }
template <class T> inline void print(const vector<T>& v) { for (auto it = v.begin(); it != v.end(); ++it) { if (it != v.begin()) { cout << " "; } cout << *it; } print(); }
template <class T, class... Args> inline void print(const T& x, const Args& ... args) { cout << x << " "; print(args...); }
#ifdef MINATO_LOCAL
template <class T1, class T2> ostream& operator<<(ostream& os, pair<T1, T2> p) { return os << "(" << p.first << ", " << p.second << ")"; }
template <size_t N, class TUPLE> void debug_tuple(ostream& os, TUPLE _) { (void)os; (void)_; }
template <size_t N, class TUPLE, class T, class ...Args> void debug_tuple(ostream &os, TUPLE t) { os << (N == 0 ? "" : ", ") << get<N>(t); debug_tuple<N + 1, TUPLE, Args...>(os, t); }
template <class ...Args> ostream& operator<<(ostream& os, tuple<Args...> t) { os << "("; debug_tuple<0, tuple<Args...>, Args...>(os, t); return os << ")"; }
string debug_delim(int& i) { return i++ == 0 ? "" : ", "; }
#define debug_embrace(x) { int i = 0; os << "{";  { x } return os << "}"; }
template <class T> ostream& operator<<(ostream& os, vector<T> v) { debug_embrace( for (T e : v) { os << debug_delim(i) << e; } ) }
template <class T, size_t N> ostream& operator<<(ostream& os, array<T, N> a) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) }
template <class T, size_t N> enable_if_t<!is_same_v<char, remove_cv_t<T>>, ostream>& operator<<(ostream& os, T(&a)[N]) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) }
template <class Key> ostream& operator<<(ostream& os, set<Key> s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) }
template <class Key, class T> ostream& operator<<(ostream& os, map<Key, T> mp) { debug_embrace( for (auto e : mp) { os << debug_delim(i) << e; }) }
template <class Key> ostream& operator<<(ostream& os, multiset<Key> s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) }
template <class T> ostream& operator<<(ostream& os, queue<T> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.front(); } ) }
template <class T> ostream& operator<<(ostream& os, deque<T> q) { debug_embrace( for (T e : q) { os << debug_delim(i) << e; } ) }
template <class T> ostream& operator<<(ostream& os, priority_queue<T> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) }
template <class T> ostream& operator<<(ostream& os, priority_queue<T, vector<T>, greater<T>> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) }
void debug_out() { cerr << endl; }
template <class T, class... Args> void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); }
#define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__)
#else
#define debug(...) (void(0))
#endif
struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); }; } fast_ios_;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

template<class T, class U, class F, class G, class H>
struct LazySegmentTree {
  private:
    F op;
    G mapping;
    H composition;
    T e;
    U id;
    int _n, size ,log;
    vector<T> node;
    vector<U> lazy;

  public:
    LazySegmentTree() {}
    LazySegmentTree(const F& op, const G& mapping, const H& composition, T e, U id, int n)
                    : LazySegmentTree(op, mapping, composition, e, id, vector<T>(n, e)) {}
    LazySegmentTree(const F& op, const G& mapping, const H& composition, T e, U id, const vector<T>& v) 
                    : op(op), mapping(mapping), composition(composition), e(e), id(id),
                    _n(int(v.size())), log(0) {
                        while ((1<<log) < _n) log++;
                        size = 1 << log;
                        node = vector<T>(2 * size, e);
                        lazy = vector<U>(size, id);
                        for (int i = 0; i < _n; i++) node[size + i] = v[i];
                        for (int i = size - 1; i >= 1; i--) {
                            update(i);
                        }
                    }
    
    void set(int p, T x) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        node[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    // [l, r) (0-indexed)
    T get(int l, int r) {
        if (l >= r) return e;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push(r >> i);
        }

        T sml = e, smr = e;
        while (l < r) {
            if (l & 1) sml = op(sml, node[l++]);
            if (r & 1) smr = op(node[--r], smr);
            l >>= 1;
            r >>= 1;
        }

        return op(sml, smr);
    }

    T all_get() const { return node[1]; }

    void apply(int p, U val) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        node[p] = val == id ? node[p] : mapping(node[p], val);
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    void apply(int l, int r, U val) {
        if (l >= r) return;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        {
            int l2 = l, r2 = r;
            while (l < r) {
                if (l & 1) all_apply(l++, val);
                if (r & 1) all_apply(--r, val);
                l >>= 1;
                r >>= 1;
            }
            l = l2;
            r = r2;
        }

        for (int i = 1; i <= log; i++) {
            if (((l >> i) << i) != l) update(l >> i);
            if (((r >> i) << i) != r) update((r - 1) >> i);
        }
    }

    template <typename C> 
    int max_right(int l, const C& check) {
        assert(0 <= l && l <= _n);
        assert(check(e));
        if (l == _n) return _n;
        l += size;
        for (int i = log; i >= 1; i--) push(l >> i);
        T sm = e;
        do {
            while (~l & 1) l >>= 1;
            if (!check(op(sm, node[l]))) {
                while (l < size) {
                    push(l);
                    l = (2 * l);
                    if (check(op(sm, node[l]))) {
                        sm = op(sm, node[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, node[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <typename C>
    int min_left(int r, const C& check) {
        assert(0 <= r && r <= _n);
        assert(check(e));
        if (r == 0) return 0;
        r += size;
        for (int i = log; i >= 1; i--) push((r - 1) >> i);
        T sm = e;
        do {
            r--;
            while (r > 1 && (r & 1)) r >>= 1;
            if (!check(op(node[r], sm))) {
                while (r < size) {
                    push(r);
                    r = (2 * r + 1);
                    if (check(op(node[r], sm))) {
                        sm = op(node[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(node[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

    T operator[](int p) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        return node[p];
    }

  private:
    
    void update(int k) { node[k] = op(node[2 * k], node[2 * k + 1]); }

    void all_apply(int k, U val) {
        node[k] = val == id ? node[k] : mapping(node[k], val);
        if (k < size) lazy[k] = composition(lazy[k], val);
    }

    void push(int k) {
        if (lazy[k] == id) return;
        all_apply(2 * k, lazy[k]);
        all_apply(2 * k + 1, lazy[k]);
        lazy[k] = id;
    }  
};

constexpr ll INF = TEN(18);
void naive() {
    int N,K; cin >> N >> K;
    vec<ll> A(N);
    rep(i,N) cin >> A[i];

    ll ans = INF;
    int pos = 0;
    rep(n,N) {
        ll tmp = 0;
        rep(i,N) {
            if (i < K) tmp += abs(A[i]-A[n]);
            else tmp -= abs(A[i]-A[n]);
        }
        if (chmin(ans,tmp)) {
            pos = n;
        }
        tmp = 0;
        rep(i,N) {
            if (i < N-K) tmp -= abs(A[i]-A[n]);
            else tmp += abs(A[i]-A[n]);
        }
        if (chmin(ans,tmp)) {
            pos = n;
        }
    }
    debug(ans,pos);
}

void solve() {
    int N,K; cin >> N >> K;
    vec<ll> A(N);
    rep(i,N) cin >> A[i];

    ll ans = INF;

    auto calc=[&]() {
        auto f=[](pll a, pll b) {return pll(a.first+b.first,a.second+b.second);};
        auto g=[](pll a, ll val) {return pll(a.first+val*a.second,a.second);};
        auto h=[](ll a, ll b) {return a+b;};
        const pll e = pll(0,0);
        const ll id = 0;
        LazySegmentTree seg(f,g,h,e,id,N);
        rep(i,N) {
            seg.set(i,pll(A[i]-A[0],1));
        }
        {
            ll val1 = seg.get(0,K).first - seg.get(K,N).first;
            ll val2 = - seg.get(0,N-K).first + seg.get(N-K,N).first;
            chmin(ans,min(val1,val2));
        }
        for (int i = 1; i < N; i++) {
            ll tmp = seg[i].first;
            seg.apply(0,i,tmp);
            seg.apply(i,N,-tmp);
            ll val1 = seg.get(0,K).first - seg.get(K,N).first;
            ll val2 = - seg.get(0,N-K).first + seg.get(N-K,N).first;
            chmin(ans,min(val1,val2));
        }
    };
    calc();
    cout << ans << ln;
}
int main() {
    //naive();
    solve();
}