import std.conv, std.functional, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


void bAdd(T)(T[] bit, int pos, T val)
in {
  assert(0 <= pos && pos < bit.length, "bAdd: 0 <= pos < |bit| must hold");
}
do {
  for (int x = pos; x < bit.length; x |= x + 1) {
    bit[x] += val;
  }
}

// sum of [0, pos)
T bSum(T)(T[] bit, int pos)
in {
  assert(0 <= pos && pos <= bit.length, "bSum: 0 <= pos <= |bit| must hold");
}
do {
  T sum = 0;
  for (int x = pos - 1; x >= 0; x = (x & (x + 1)) - 1) {
    sum += bit[x];
  }
  return sum;
}

// min pos s.t. pred(sum of [0, pos))
T bBinarySearch(alias pred, T)(T[] bit)
in {
  assert(!(bit.length & (bit.length - 1)),
         "bBinarySearch: |bit| must be a power of 2");
}
do {
  import std.functional : unaryFun;
  alias predFun = unaryFun!pred;
  if (predFun(0)) return 0;
  if (!predFun(bit[$ - 1])) return cast(int)(bit.length) + 1;
  int lo = 0, hi = cast(int)(bit.length);
  T sum = 0;
  for (; lo + 1 < hi; ) {
    const mid = (lo + hi) >> 1;
    if (predFun(sum + bit[mid - 1])) {
      hi = mid;
    } else {
      lo = mid;
      sum += bit[mid - 1];
    }
  }
  return hi;
}


enum INF = 10L^^18;

int N, K;
long[] A;

void main() {
  try {
    for (; ; ) {
      N = readInt();
      K = readInt();
      A = new long[N];
      foreach (i; 0 .. N) {
        A[i] = readLong();
      }
      
      auto as = new Tuple!(long, int)[N];
      foreach (i; 0 .. N) {
        as[i] = tuple(A[i], i);
      }
      as.sort;
      auto poss = new int[N];
      foreach (i; 0 .. N) {
        poss[as[i][1]] = i;
      }
      
      int bitN;
      for (bitN = 1; bitN < N; bitN <<= 1) {}
      auto bitCnt = new int[bitN];
      auto bitSum = new long[bitN];
      long ans = INF;
      foreach (i; 0 .. N) {
        bitCnt.bAdd(poss[i], +1);
        bitSum.bAdd(poss[i], +A[i]);
        if (i >= K - 1) {
          const med = bitCnt.bBinarySearch!(cnt => (cnt >= (K + 1) / 2));
          const aMed = as[med - 1][0];
          const cntL = bitCnt.bSum(med);
          const sumL = bitSum.bSum(med);
          long cost;
          cost += (cntL * aMed - sumL);
          cost += ((bitSum.bSum(bitN) - sumL) - (K - cntL) * aMed);
          debug {
            writefln("[%s, %s]: %s %s", i - K + 1, i, aMed, cost);
          }
          chmin(ans, cost);
          bitCnt.bAdd(poss[i - K + 1], -1);
          bitSum.bAdd(poss[i - K + 1], -A[i - K + 1]);
        }
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}