#include <bits/stdc++.h>
using namespace std;

using V = pair<int, int64_t>;

V merge(const V &l, const V &r) {
  return {l.first + r.first, l.second + r.second};
}

struct SegmentTree {
  const int n;
  const V unit_value = {0, 0};
  vector<V> val;

  SegmentTree(int _n) : n(1 << (33-__builtin_clz(_n-1))), val(n, unit_value) {}

  void update(int i, const V &v) {
    i += n / 2;
    val[i] = merge(val[i], v);
    while (i > 1) {
      i >>= 1;
      val[i] = merge(val[i * 2 + 0], val[i * 2 + 1]);
    }
  }

  V query(int l, int r) const {
    l = max(0, min(n / 2, l)) + n / 2;
    r = max(0, min(n / 2, r)) + n / 2;
    V ret = unit_value;
    for (; l < r; l >>= 1, r >>= 1) {
      if (l & 1) ret = merge(ret, val[l++]);
      if (r & 1) ret = merge(ret, val[--r]);
    }
    return ret;
  }
};

int64_t solve(const int n, const int k, const vector<int> &A) {
  if (k == 1) return 0;

  vector<int> compressor(A);
  {
    sort(compressor.begin(), compressor.end());
    compressor.erase(unique(compressor.begin(), compressor.end()), compressor.end());
  }
  auto compress = [&compressor](int i) {
    return lower_bound(compressor.begin(), compressor.end(), i) - compressor.begin();
  };

  int m = compressor.size();

  int num_medians = n - k + 1;
  vector<int> medians(num_medians);
  {
    multiset<int> S(&A[0], &A[k]);
    auto it = next(S.begin(), k / 2);

    for (int i = k; i <= n; i++) {
      medians[i - k] = *it;
      S.insert(A[i]);
      if (A[i] <  *it) it--;
      if (A[i-k] <= *it) it++;
      S.erase(S.lower_bound(A[i-k]));
    }
  }

  SegmentTree seg(m);

  int64_t ans = 1e18;

  for (int i = 0; i < n; i++) {
    int a = A[i];
    seg.update(compress(a), {1, a});

    if (i >= k) {
      int c = A[i-k];
      seg.update(compress(c), {-1, -c});
    }

    if (i >= k - 1) {
      int64_t median = medians[i-k+1];
      int median_c = compress(median);

      V lower = seg.query(0, median_c);
      V higher = seg.query(median_c, m);

      int64_t inc_cost = median * lower.first - lower.second;
      int64_t dec_cost = higher.second - median * higher.first;
      int64_t cand = inc_cost + dec_cost;

      ans = min(ans, cand);
    }
  }
  return ans;
}

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);

  int n, k; cin >> n >> k;
  vector<int> A(n);
  for (int i = 0; i < n; i++) cin >> A[i];

  cout << solve(n, k, A) << endl;

  return 0;
}