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

points = []
mu_x = 0.0
mu_y = 0.0
cov_xy = 0.0
for i in range(n):
  points.append((i, a[i]))
  mu_x += i
  mu_y += a[i]
  cov_xy += i * a[i]

mu_x /= n
mu_y /= n
cov_xy = cov_xy / n - mu_x * mu_y

sigma2_x = 0.0
for x, y in points:
  sigma2_x += (x - mu_x) ** 2

sigma2_x /= n

d = cov_xy / sigma2_x
b1 = mu_y - d * mu_x
c = sum([(b1 + i * d - points[i][1]) ** 2 for i in range(n)])
print("{:.7f} {:.7f}".format(b1, d))
print("{:.7f}".format(c))