N = int(input())
P = list(map(int, input().split()))

if len(set(P)) == 1:
    print(1)
    exit()

q1, q2 = int(N / 4), int(N / 4 * 3)
p1, p2 = P[q1], P[q2]

ans = 0
for p in P:
    ans += min(abs(p - p1), abs(p - p2))
print(ans)