#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n, k; cin >> n >> k;
  vector<int> a(n); REP(i, n) cin >> a[i];
  if (k == 0) {
    ll ans1 = 0, ans2 = 0;
    REP(i, n) ans1 += a[i] - a[0];
    REP(i, n) ans2 += a[n - 1] - a[i];
    cout << -max(ans1, ans2) << '\n';
    return 0;
  }
  ll sum = 0;
  REP(i, n) sum += (a[i] - a[0]) * (i < k ? 1 : -1);
  ll l_out = 0, l_in = 0, r_out = 0, r_in = 0;
  REP(i, k) r_in += a[i];
  FOR(i, k, n) r_out += a[i];
  int l = 0, r = k - 1;
  ll ans = sum;
  FOR(i, 1, n) {
    assert(l < i);
    r_in -= a[i - 1];
    l_in += a[i - 1];
    while (l < i && r + 1 < n && a[r + 1] - a[i] <= a[i] - a[l]) {
      r_out -= a[r + 1];
      r_in += a[r + 1];
      ++r;
      l_in -= a[l];
      l_out += a[l];
      ++l;
    }
    chmin(ans, -(r_out - 1LL * a[i] * (n - r - 1))
               + (r_in - 1LL * a[i] * (r - i + 1))
               + (1LL * a[i] * (i - l) - l_in)
               - (1LL * a[i] * l - l_out));
  }
  cout << ans << '\n';
  return 0;
}