import math
n = int(raw_input())
l = map(int, raw_input().split())
d = int(math.sqrt(sum(l)))
p = 0
m = 0
for i in range(n):
    if i < d:
        t = i + 1
    elif i < 2 * d - 1:
        t = 2 * d - (i + 1)
    else:
        t = 0
    if l[i] > t:
        p += l[i] - t
    elif t > l[i]:
        m += t - l[i]
print max(p,m)