import numpy as np
n = int(input())
x = np.arange(n)
y = np.array(input().split(), dtype=np.intc)
(b, a), error, _, _, _ = np.polyfit(x, y, deg=1, full=True)
print("{:.12f} {:.12f}".format(a, b))
print("{:.12f}".format(*error))