class Fenwick_Tree:
    def __init__(self, n):
        self._n = n
        self.data = [0] * n
 
    def add(self, p, x):
        assert 0 <= p < self._n
        p += 1
        while p <= self._n:
            self.data[p - 1] += x
            p += p & -p
 
    def sum(self, l, r):
        assert 0 <= l <= r <= self._n
        return self._sum(r) - self._sum(l)
 
    def _sum(self, r):
        s = 0
        while r > 0:
            s += self.data[r - 1]
            r -= r & -r
        return s
    
    def get(self, k):
        k += 1
        x, r = 0, 1
        while r < self._n:
            r <<= 1
        len = r
        while len:
            if x + len - 1 < self._n:
                if self.data[x + len - 1] < k:
                    k -= self.data[x + len - 1]
                    x += len
            len >>= 1
        return x
    
    
from bisect import *
from copy import *
def compress(lst):
    B = []
    D = dict()
    vals = deepcopy(lst)
    vals = list(set(vals))
    vals.sort()
    for i in range(len(lst)):
        ind = bisect_left(vals, lst[i])
        B.append(ind)
    for i in range(len(B)):
        D[lst[i]] = B[i]
    return B, D, vals


N, K = map(int, input().split())
A = list(map(int, input().split())) + [-1]
A, _, itov = compress(A)
Ts = Fenwick_Tree(N + 5)
Tn = Fenwick_Tree(N + 5)
for i in range(K):
    Ts.add(A[i], itov[A[i]])
    Tn.add(A[i], 1)
    
ind = Tn.get(K//2)
ans = Ts.sum(ind + 1, N + 5) - Ts.sum(0, ind) + itov[ind] * (Tn.sum(0, ind) - Tn.sum(ind+1, N + 5))
for i in range(K, N):
    Ts.add(A[i-K], -itov[A[i-K]])
    Ts.add(A[i], itov[A[i]])
    Tn.add(A[i-K], -1)
    Tn.add(A[i], 1)
    ind = Tn.get(K//2)
    val = itov[ind]
    ans = min(ans, Ts.sum(ind + 1, N + 5) - Ts.sum(0, ind) + val * (Tn.sum(0, ind) - Tn.sum(ind+1, N + 5)))
 
print(ans)