n=int(input())
a=list(map(int,input().split()))
a.sort()
dp=[]
med=len(a)//2
for i in range(n):
    if n%2!=0:
        dp.append(abs(a[i]-a[med]))
    else:
        med_i=(a[med]+a[med-1])//2
        dp.append(abs(a[i]-med_i))
print(sum(dp))