N = int(input())
Y = list(map(int, input().split()))
Y.sort()
if N & 1 == 1:
    m = Y[N//2]
else:
    m = (Y[N//2 - 1] + Y[N//2] + 1) // 2
s = 0
for i in range(N):
    s += abs(m - Y[i])
print(s)