def calc(A, n):
    val = 0
    for a in A:
        val += abs(A[n] - a)
    return val 

N = int(input())
Y = list(map(int, input().split()))
Y.sort()
if N % 2:
    print(calc(Y, N//2))
else:
    print(min(calc(Y, N//2), calc(Y, N//2 - 1)))