#include <bits/stdc++.h>
using namespace std;
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
#ifdef __LOCAL
#define debug(x) cerr << __LINE__ << ": " << #x << " = " << x << endl
#define debugArray(x, n)                           \
  cerr << __LINE__ << ": " << #x << " = {";        \
  for (long long hoge = 0; (hoge) < (n); ++(hoge)) \
    cerr << ((hoge) ? "," : "") << x[hoge];        \
  cerr << "}" << endl
#else
#define debug(x) (void(0))
#define debugArray(x, n) (void(0))
#endif

#define TEST(s)                            \
  if (!(s)) {                              \
    cout << __LINE__ << " " << #s << endl; \
    exit(-1);                              \
  }
double tick() {
  static clock_t oldtick;
  clock_t newtick = clock();
  double diff = 1.0 * (newtick - oldtick) / CLOCKS_PER_SEC;
  oldtick = newtick;
  return diff;
}

template <typename T>
struct BinaryIndexedTree {
  vector<T> dat;
  BinaryIndexedTree(int n) : dat(n + 1, 0) {}
  BinaryIndexedTree(int n, T a) : BinaryIndexedTree(vector<T>(n, a)) {}
  BinaryIndexedTree(vector<T> y) : dat(y.size() + 1) {
    for (int i = 0; i < y.size(); ++i) dat[i + 1] = y[i];
    for (int i = 1; i + (i & -i) < dat.size(); ++i) dat[i + (i & -i)] += dat[i];
  }
  void add(int i, T a = 1) {
    for (++i; i < (int)dat.size(); i += i & -i) dat[i] += a;
  }
  T sum(int i) {  // sum [0,i)
    T s = 0;
    for (; i > 0; i &= i - 1) s += dat[i];
    return s;
  }
  // min { i : sum(i+1) > k } -> kth element(0-indexed)
  int find(T k) const {
    int i = 0;
    for (int p = 1 << (__lg(dat.size() - 1) + 1); p > 0; p >>= 1)
      if (i + p < (int)dat.size() && dat[i + p] <= k) k -= dat[i += p];
    return i + 1 == (int)dat.size() ? -1 : i;  // -1 -> no solutions
  }
};

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  int N, K;
  cin >> N >> K;
  long long A[N];
  for (int i = 0; i < N; i++) cin >> A[i];
  vector<long long> vec(A, A + N);
  sort(vec.begin(), vec.end());
  vec.erase(unique(vec.begin(), vec.end()), vec.end());
  auto id = [&](int x) {
    return lower_bound(vec.begin(), vec.end(), x) - vec.begin();
  };
  BinaryIndexedTree<long long> bit1(vec.size()), bit2(vec.size());
  long long ans = LLONG_MAX / 10;
  long long sum = 0;
  for (int i = 0; i < N; i++) {
    int idx = id(A[i]);
    bit1.add(idx, 1);
    bit2.add(idx, A[i]);
    sum += A[i];
    if (i >= K - 1) {
      int med = bit1.find(K / 2);
      int lcnt = bit1.sum(med), hcnt = K - lcnt;
      long long lsum = bit2.sum(med), hsum = sum - lsum;
      long long low = lcnt * vec[med] - lsum;
      long long high = hsum - hcnt * vec[med];
      ans = min(ans, low + high);
      int jdx = id(A[i - K + 1]);
      bit1.add(jdx, -1);
      bit2.add(jdx, -A[i - K + 1]);
      sum -= A[i - K + 1];
    }
  }
  cout << ans << "\n";
  return 0;
}