#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <deque>
#include <queue>
#include <array>
#include <set>
#include <map>
#include <cmath>
#include <algorithm>
#include <numeric>
#include <cassert>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cstdint>

using namespace std;
using i64 = int64_t;
using i32 = int32_t;
template<class T, class U> void init_n(vector<T>& v, size_t n, U x) 
{ v = vector<T>(n, x); }
template<class T> void init_n(vector<T>& v, size_t n) { init_n(v, n, T()); }
template<class T> void read_n(vector<T>& v, size_t n, size_t o = 0) 
{ v = vector<T>(n+o); for (size_t i=o; i<n+o; ++i) cin >> v[i]; }
template<class T> void read_n(T a[], size_t n, size_t o = 0)
{ for (size_t i=o; i<n+o; ++i) cin >> a[i]; }
template<class T> T gabs(const T& x) { return max(x, -x); }
#define abs gabs

i64 n, k;
vector<i64> a;
int main() {
  cin >> n >> k;
  read_n(a, n);
  multiset<i64> lq, hq;
  i64 ans = 1ll << 60, ls = 0, hs = 0;
  for (i64 i = 0; i < n; ++i) {
    if (i - k >= 0) {
      i64 y = a[i - k];
      auto lit = lq.find(y);
      if (lit != lq.end()) {
        lq.erase(lq.find(y));
        ls -= y;
      } else {
        hq.erase(hq.find(y));
        hs -= y;
      }
    }
    i64 x = a[i];
    if (lq.empty() || x <= *(lq.rbegin())) {
      lq.insert(x);
      ls += x;
    } else {
      hq.insert(x);
      hs += x;
    }
    while (lq.size() < hq.size()) {
      i64 d = *(hq.begin());
      lq.insert(d);
      hq.erase(hq.begin());
      ls += d;
      hs -= d;
    }
    while (lq.size() > hq.size()) {
      i64 d = *(lq.rbegin());
      hq.insert(d);
      lq.erase(--(lq.end()));
      hs += d;
      ls -= d;
    }
    if (i + 1 >= k) {
      i64 med = *(hq.begin());
      i64 scr = lq.size() * med - ls + hs - hq.size() * med;
      ans = min(ans, abs(scr));
    }
  }
  cout << ans << '\n';
  return 0;
}