from statistics import median
import math
n,k=map(int,input().split())
a=list(map(int,input().split()))
c=0
for i in range(0,n-k+1):
    s=a[i:i+k]
    t=median(s)
    b=math.ceil(t)
    d=math.floor(t)
    e=0
    f=0
    for u in range(0,k):
        e+=abs(b-a[i+u])
        f+=abs(d-a[i+u])
    else:
        if i==1:
            c=min(e,f)
        else:
            c=min(e,f,c)
else:
    print(c)