#!/usr/bin/ python3.8
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


class BinaryIndexedTree():
    def __init__(self, seq):
        self.size = len(seq)
        self.depth = self.size.bit_length()
        self.build(seq)

    def build(self, seq):
        data = seq
        size = self.size
        for i, x in enumerate(data):
            j = i + (i & (-i))
            if j < size:
                data[j] += data[i]
        self.data = data

    def __repr__(self):
        return self.data.__repr__()

    def get_sum(self, i):
        data = self.data
        s = 0
        while i:
            s += data[i]
            i -= i & -i
        return s

    def add(self, i, x):
        data = self.data
        size = self.size
        while i < size:
            data[i] += x
            i += i & -i

    def find_kth_element(self, k):
        data = self.data
        size = self.size
        x, sx = 0, 0
        dx = 1 << (self.depth)
        for i in range(self.depth - 1, -1, -1):
            dx = (1 << i)
            if x + dx >= size:
                continue
            y = x + dx
            sy = sx + data[y]
            if sy < k:
                x, sx = y, sy
        return x + 1


N, K, *A = map(int, read().split())
sortedA = sorted(set(A))
elem_rank = {x: i for i, x in enumerate(sortedA, 1)}

bit_num = BinaryIndexedTree([0] * (N + 10))
bit_sum = BinaryIndexedTree([0] * (N + 10))

total = 0
for x in A[:K - 1]:
    r = elem_rank[x]
    bit_num.add(r, 1)
    bit_sum.add(r, x)
    total += x

answer = 10 ** 15
for add_x, rm_x in zip(A[K - 1:], A):
    add_r = elem_rank[add_x]
    rm_r = elem_rank[rm_x]
    bit_num.add(add_r, 1)
    bit_sum.add(add_r, add_x)
    total += add_x
    n = (K + 1) // 2
    median_r = bit_num.find_kth_element(n)
    median = sortedA[median_r - 1]
    nl = bit_num.get_sum(median_r)
    nr = K - nl
    sl = bit_sum.get_sum(median_r)
    sr = total - sl
    cost = (nl * median - sl) + (sr - nr * median)
    if answer > cost:
        answer = cost
    bit_num.add(rm_r, -1)
    bit_sum.add(rm_r, -rm_x)
    total -= rm_x

print(answer)