import math

n = int(input())
a = list(map(int, input().split()))
sum_blocks = sum(a)
level = int(math.sqrt(sum_blocks))

total = float('inf')

for i in range(level - 1, level):
    t = 0
    for j in range(n):
        h = a[j] if 0 <= j < n else 0
        base = level - abs(i - j) if level >= abs(i - j) else 0
        if h > base:
            t += h - base
    total = min(total, t)

print(total)