n = int(input())
a = list(map(int, input().split()))

sum_a = sum(a)
sum_jm1 = n * (n - 1) // 2
sum_jm1_sq = (n - 1) * n * (2 * n - 1) // 6
sum_ajm = sum(a[i] * i for i in range(n))

denominator = n * sum_jm1_sq - sum_jm1 ** 2

d_numerator = n * sum_ajm - sum_jm1 * sum_a
b1_numerator = sum_jm1_sq * sum_a - sum_jm1 * sum_ajm

d = d_numerator / denominator
b1 = b1_numerator / denominator

cost = 0.0
for i in range(n):
    expected = b1 + i * d
    cost += (a[i] - expected) ** 2

# Print with sufficient precision
print("{0:.15f} {1:.15f}".format(b1, d))
print("{0:.15f}".format(cost))