#BIT plus ver
class BITplus:
    def __init__(self,N):
        self.N = N
        self.bit = [0] * (self.N+1)
    def add(self,i,x):
        while i <= self.N:
            self.bit[i] += x
            i += i & -i
    def fold(self,i):
        ans = 0
        while i > 0:
            ans += self.bit[i]
            i -= i & -i
        return ans
    def lb(self,w):
        if w <= 0:return 0
        x = 0
        k = 1
        while k <= self.N:
            k <<= 1
        k >>= 1
        while k:
            if x + k <= self.N and self.bit[x+k] < w:
                w -= self.bit[x+k]
                x += k
            k >>= 1
        return x + 1

    #サイズ N の配列をいれる
    def build(self,seq):
        bit = self.bit
        N = self.N
        for i in range(N):
            bit[i+1] = seq[i]
        for i in range(1,N+1):
            if i + (i & -1) <= N:
                bit[i + (i & -i)] += bit[i]

N,K = map(int,input().split())
A = list(map(int,input().split()))
rD = sorted(set(A))
D = {v:i for i,v in enumerate(rD)}
n = len(D)
bit1 = BITplus(n)
bit2 = BITplus(n)
mid = (K+1) // 2
for i in range(K):
    a = A[i]
    bit1.add(D[a]+1,1)
    bit2.add(D[a]+1,a)
ans = 10 ** 18
for i in range(K-1,N):
    if i >= K:
        a = A[i]
        b = A[i-K]
        bit1.add(D[a]+1,1)
        bit2.add(D[a]+1,a)
        bit1.add(D[b]+1,-1)
        bit2.add(D[b]+1,-b)
    m = bit1.lb(mid)
    mm = bit1.fold(m)
    t1 = bit2.fold(m)
    t2 = bit2.fold(n) - t1
    tmp = rD[m-1] * mm - t1 + t2 - rD[m-1] * (K - mm)
    if tmp < ans:
        ans = tmp
    #print(m,mm,t1,t2,tmp)
print(ans)