import bisect

ans = 10**20

N, K = list(map(int, input().split()))
x = [-10**20] + list(map(int, input().split())) + [10**20]

zero = bisect.bisect_left(x, 0)

left = x[:zero] + [0] 
right = [0] + x[zero:]
left.reverse()
l = len(left)
r = len(right)

idxs = [[K-i, i] for i in range(K+1) if K-i < l and i < r]

for l, r in idxs:
    n = abs(left[l]) + right[r] + min(abs(left[l]), right[r])
    ans = min(ans, n)
print(ans)