n = int(input())
a = list(map(int, input().split()))

a = sorted(a)
if n % 2 == 0:
    median = (a[n//2 - 1] + a[n//2]) / 2
else:
    median = a[n//2]

ans = 0
for i in range(n):
    ans += abs(a[i] - median)

print(int(ans))