#include <bits/stdc++.h>
//#include <atcoder/all>
//using namespace atcoder;
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<int, int> pii;
typedef pair<long long, long long> PLL;
typedef pair<int, PII> TIII;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;


#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()

#define MOD 1000000007

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;}
const double EPS = 1e-9, PI = acos(-1);
const double pi = 3.141592653589793238462643383279;
//ここから編集    
typedef string::const_iterator State;
ll GCD(ll a, ll b){
  return (b==0)?a:GCD(b, a%b);
}
ll LCM(ll a, ll b){
  return a/GCD(a, b) * b;
}
template< int mod >
struct ModInt {
  int x;

  ModInt() : x(0) {}

  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

  ModInt &operator+=(const ModInt &p) {
    if((x += p.x) >= mod) x -= mod;
    return *this;
  }

  ModInt &operator-=(const ModInt &p) {
    if((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }

  ModInt &operator*=(const ModInt &p) {
    x = (int) (1LL * x * p.x % mod);
    return *this;
  }

  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }

  ModInt operator-() const { return ModInt(-x); }

  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

  bool operator==(const ModInt &p) const { return x == p.x; }

  bool operator!=(const ModInt &p) const { return x != p.x; }

  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while(b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }

  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while(n > 0) {
      if(n & 1) ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }

  friend ostream &operator<<(ostream &os, const ModInt &p) {
    return os << p.x;
  }

  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt< mod >(t);
    return (is);
  }

  static int get_mod() { return mod; }
};

using modint = ModInt< 998244353 >;
template< typename T >
struct Combination {
  vector< T > _fact, _rfact, _inv;

  Combination(int sz) : _fact(sz + 1), _rfact(sz + 1), _inv(sz + 1) {
    _fact[0] = _rfact[sz] = _inv[0] = 1;
    for(int i = 1; i <= sz; i++) _fact[i] = _fact[i - 1] * i;
    _rfact[sz] /= _fact[sz];
    for(int i = sz - 1; i >= 0; i--) _rfact[i] = _rfact[i + 1] * (i + 1);
    for(int i = 1; i <= sz; i++) _inv[i] = _rfact[i] * _fact[i - 1];
  }

  inline T fact(int k) const { return _fact[k]; }

  inline T rfact(int k) const { return _rfact[k]; }

  inline T inv(int k) const { return _inv[k]; }

  T P(int n, int r) const {
    if(r < 0 || n < r) return 0;
    return fact(n) * rfact(n - r);
  }

  T C(int p, int q) const {
    if(q < 0 || p < q) return 0;
    return fact(p) * rfact(q) * rfact(p - q);
  }

  T H(int n, int r) const {
    if(n < 0 || r < 0) return (0);
    return r == 0 ? 1 : C(n + r - 1, r);
  }
};
struct WaveletMatrix {
  struct BitVector{
    // 大ブロックを 256, 小ブロックを8としておく

    const uint64_t BLOCK_BITNUM = 256;
    const uint64_t TABLE_INTERVAL = 8;

    const uint64_t NOT_FOUND = 0xFFFFFFFFFFFFFFFFLLU; /* selectで使う */

    uint64_t length;
    vector<uint64_t> bits; /* 元のbit列を圧縮したもの */
    vector<uint32_t> blocks; /* 1つ目の補助データに該当するもの */
    vector<uint64_t> tables; /* 2つ目の補助データに該当するもの */

    BitVector() : length(0){}
    BitVector(uint64_t N){
      init(N);
    }
    void init(uint64_t N) {
      length = N;
      uint64_t block_num = (N + BLOCK_BITNUM - 1) / (BLOCK_BITNUM);
      blocks.assign(block_num+1,0); 

      uint64_t bits_len = (N + TABLE_INTERVAL - 1) / (TABLE_INTERVAL);
      bits.assign(bits_len+1,0);
      tables.assign(bits_len+1,0);

      //cerr << blocks.size() << " " << bits.size() << endl;      
    }

    void build(){
      uint64_t block_ind, offset, table_ind, sz = (length + BLOCK_BITNUM - 1) / (BLOCK_BITNUM);
      blocks[0] = 0;
      for(block_ind=0; block_ind < sz; block_ind++){
        tables[block_ind * BLOCK_BITNUM / TABLE_INTERVAL] = 0;
        table_ind = (block_ind * BLOCK_BITNUM) / TABLE_INTERVAL;
        for(offset=0; offset<BLOCK_BITNUM && table_ind+1 < tables.size() ; offset+=TABLE_INTERVAL){
          /* 現在見る位置はblock_ind * BLOCK_BITNUM + offset */
          tables[table_ind + 1] = tables[table_ind] + __builtin_popcountll(bits[table_ind]);
          table_ind++;  
        }
        blocks[block_ind + 1] = blocks[block_ind] + tables[table_ind];
      }
      if(block_ind * BLOCK_BITNUM / TABLE_INTERVAL < tables.size())
        tables[block_ind * BLOCK_BITNUM / TABLE_INTERVAL] = 0;
      
    }

    void set(uint64_t b, uint64_t pos){
      assert(pos >= 0 && pos < length);
      uint64_t block_ind = pos / TABLE_INTERVAL;
      uint64_t offset = pos % TABLE_INTERVAL;

      if(b == 1) bits[block_ind] |= (1UL << offset);
      else bits[block_ind] &= ~(1UL << offset);
    }

    int access(uint64_t pos){
      assert(pos >= 0 && pos < length);
      uint64_t block_ind = pos / TABLE_INTERVAL;
      uint64_t offset = pos % TABLE_INTERVAL;

      return (bits[block_ind] >> offset) & 1;
    }

    /* [0,pos)の1の数 */
    uint64_t rank(uint64_t bit, uint64_t pos){
      uint64_t block_ind = pos / BLOCK_BITNUM;
      uint64_t table_ind = pos / TABLE_INTERVAL;

      uint64_t offset = pos % TABLE_INTERVAL;
      uint64_t m = (bits[table_ind] & ((1UL << offset) - 1));
      
      return bit ? blocks[block_ind] + tables[table_ind] + __builtin_popcountll(m) : pos - rank(1,pos);
    }
    
    uint64_t rank(uint64_t bit, uint64_t l, uint64_t r){
      return rank(bit, r) - rank(bit, l); 
    }

  };
  
  uint64_t length;
  uint64_t height;
  uint64_t sigma;
  vector<BitVector> B; /* 各高さの索引 */
  vector<uint64_t> zerosum; /* 各高さにおける0の数 */
  vector<vector<uint64_t>> cums;
  WaveletMatrix(){}
  WaveletMatrix(vector<uint64_t> v, uint64_t _sigma) :length(v.size()), sigma(_sigma) {
    height = (sigma == 1) ? 1 : (64 - __builtin_clzll(sigma-1));
    B.resize(height); zerosum.resize(height), cums.resize(height);

    for(int i=0; i<height; i++){
      B[i].init(v.size());
      cums[i].resize(v.size()+1);
      vector<uint64_t> v0, v1;
      for(int j=0; j<v.size(); j++){
        int bi_j = (v[j] >> (height - 1 - i)) & 1;
        B[i].set(bi_j, j);
        if(bi_j == 0) v0.emplace_back(v[j]);
        else v1.emplace_back(v[j]);

        cums[i][j+1] = cums[i][j] + v[j];
      } 
      zerosum[i] = v0.size();
      for(int j=0; j<v1.size(); j++) v0.emplace_back(v1[j]);
      B[i].build();
      // for(int j=0; j<v.size(); j++) cout << B[i].access(j);
      // cout << endl;

      v = move(v0);
    }
  }

  int access(int pos){
    assert(pos >= 0 && pos < length);
    
    uint64_t res = 0;
    for(int i=0; i<height; i++){
      int bit = B[i].access(pos);
      //cout << bit << endl;
      if(bit) res |= (1UL << (height - 1 - i));

      pos = B[i].rank(bit, pos);
      
      if(bit) pos += zerosum[i];
    }
    return res;
  }
  /* [0,r)のcの数 */
  int rank(uint64_t c, int r){
    
    if(c >= sigma) return 0;
    int l = 0;
    for(int i=0; i<height; i++){
      int bit = ((c >> (height - 1 - i)) & 1);
      l = (bit?zerosum[i]:0) + B[i].rank(bit, l);
      r = (bit?zerosum[i]:0) + B[i].rank(bit, r);
    }
    return r-l;
  }
  /* [l, r)のcの数 */
  int rank(uint64_t c, int l, int r){
    if(c >= sigma) return 0;
    for(int i=0; i<height; i++){
      int bit = ((c >> (height - 1 - i)) & 1);
      l = (bit?zerosum[i]:0) + B[i].rank(bit, l);
      r = (bit?zerosum[i]:0) + B[i].rank(bit, r);
    }
    return r-l;
  }

  /* [l, r)でk(=0,1,...,r-l-1)番目に小さい値を返す */
  /* verify:https://old.yosupo.jp/problem/range_kth_smallest*/
  uint64_t kth_smallest(int l, int r, int k) {
    uint64_t res = 0;
    for(int i=0; i<height; i++){
      int num = B[i].rank(0, l, r);
      if(k < num){
        l = B[i].rank(0, l);
        r = B[i].rank(0, r);
      }else{
        l = zerosum[i] + B[i].rank(1, l);
        r = zerosum[i] + B[i].rank(1, r);
        k -= num;
        res |= (1UL << (height - 1 - i));
      }
    }
    return res;
  }

  uint64_t kth_largest(int l, int r, int k){
    return kth_smallest(l, r, r-l-k-1);
  }

  /* [l, r)中でx未満の要素の数を返す */
  
  uint64_t rank_lower(int l, int r, uint64_t x){
    uint64_t res = 0;
    for(int i=0; i<height; i++){
      int bit = (x >> (height - 1 - i) & 1);
      if(bit == 0){
        l = B[i].rank(0, l);
        r = B[i].rank(0, r);
      }else{
        res += B[i].rank(0, l, r);
        l = zerosum[i] + B[i].rank(1, l);
        r = zerosum[i] + B[i].rank(1, r);
      }
    }
    return res;
  }

  
  /* [l, r)中でx以上y未満の要素の数を返す */
  /* verify:https://codeforces.com/contest/1042/problem/D */
  uint64_t range_freq(int l, int r, uint64_t x, uint64_t y) {
    return rank_lower(l, r, y) - rank_lower(l, r, x);
  }

  /* [l, r)中でv < xを満たす最大のvを返す */
  /* verigy:http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1549*/
  uint64_t prev_value(int l, int r, uint64_t x) {
    uint64_t cnt = rank_lower(l, r, x);
    return cnt == 0 ? 1e9 : kth_smallest(l, r, cnt - 1);
  }

  /* [l, r)中でx <= vを満たす最小のvを返す */
  /* verigy:http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1549*/
  uint64_t next_value(int l, int r, uint64_t x) {
    uint64_t cnt = rank_lower(l, r, x);
    return cnt == r-l ? 1e9 : kth_smallest(l, r, cnt);
  }
};
template<typename T = int> struct BIT{
  vector<T> node;
 
  int N;
  BIT(int n){
    N = n;
    node.resize(N+1);
  }
  void add(int i, T x){
    i++;
    while(i <= N){
      node[i] += x;
      i += (i & -i);
    }
  }
  T sum(int i){
    T res = 0;
    while(i > 0){
      res += node[i];
      i -= (i & -i);
    }
    return res;
  }
};
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(12);
  
  int N, K; cin >> N >> K;
  vector<uint64_t> a(N);
  BIT<ll> sums(1010101), tot(1010101);
  REP(i,N) cin >> a[i];

  vector<ll> v;
  REP(i,N){
    v.push_back(a[i]);
  }
  sort(all(v));
  v.erase(unique(all(v)), v.end());
  WaveletMatrix wm(a, *max_element(all(a)) + 1);

  REP(i,N) a[i] = lower_bound(all(v), a[i]) - v.begin();
  for(int i=0; i<K-1; i++) {
    sums.add(a[i]+1, v[a[i]]);
    tot.add(a[i]+1, 1);
  }
  ll ans = (1LL<<60);
  for(int i=0; i+K<=N; i++){
    sums.add(a[i+K-1]+1, v[a[i+K-1]]);
    tot.add(a[i+K-1]+1, 1);
    ll c = wm.kth_smallest(i, i+K, K/2);

    int idx = upper_bound(all(v), c) - v.begin();
    ll t1 = sums.sum(idx);
    ll t2 = sums.sum(1010101) - sums.sum(idx);
    //cout << sums.sum(1010101) << " " << t1 <<  " " << t2 << endl;
    ll n1 = tot.sum(idx);
    ll n2 = tot.sum(1010101) - tot.sum(idx);
    ans = min(ans, abs(t1 - c * n1) + abs(t2 - c * n2));

    sums.add(a[i]+1, -v[a[i]]);
    tot.add(a[i]+1, -1);
  }
  cout << ans << endl;
  return 0;
}