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

Y.sort()

sum = 0
if N % 2 != 0:
	center = Y[int(N / 2) + 1]
else:
	center = int((Y[int(N / 2) - 1] + Y[int(N / 2)]) / 2)

for i in Y:
		sum += abs(i - center)

print(sum)