import sys

sys.setrecursionlimit(10**6)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.buffer.readline())
def FI(): return float(sys.stdin.buffer.readline())
def MI(): return map(int, sys.stdin.buffer.readline().split())
def MF(): return map(float, sys.stdin.buffer.readline().split())
def MI1(): return map(int1, sys.stdin.buffer.readline().split())
def LI(): return list(map(int, sys.stdin.buffer.readline().split()))
def LI1(): return list(map(int1, sys.stdin.buffer.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def BI(): return sys.stdin.buffer.readline().rstrip()
def SI(): return sys.stdin.buffer.readline().rstrip().decode()
dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
inf = 10**16
# md = 998244353
md = 10**9+7

n, k = MI()
aa = LI()

if k==0:
    a0=-sum(aa[i]-aa[0] for i in range(n))
    a1=-sum(aa[-1]-aa[i] for i in range(n))
    print(min(a0,a1))
    exit()

cs = [0]
for a in aa: cs.append(cs[-1]+a)

ans = inf
l, r = 0, k
for i, a in enumerate(aa):
    while r < n and abs(a-aa[r]) < abs(a-aa[l]): l, r = l+1, r+1
    s = i*a+cs[n]-cs[i]*2-a*(n-i)
    out = a*l-cs[l]+cs[n]-cs[r]-(n-r)*a
    cur = s-out*2
    ans = min(ans, cur)
    # print(i,a,l,r,s,out,cur)

print(ans)