N,K = map(int,input().split())
A = list(map(int,input().split()))

#Aの最小値をx
P0 = sum(A) - A[0]*N
Q0 = sum(A[K:]) - A[0]*(N-K)
#print(P0,Q0)

#Aの最大値をx
PN = A[N-1]*N - sum(A)
QN = A[N-1]*(N-K) - sum(A[:N-K])
#print(PN,QN)

ans = min(P0-2*Q0, PN-2*QN)
print(ans)