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

S0 = n
S1 = (n - 1) * n // 2
S2 = (n - 1) * n * (2 * n - 1) // 6

A0 = sum(a)
A1 = sum(j * a[j] for j in range(n))

d_numerator = S0 * A1 - S1 * A0
d_denominator = S0 * S2 - S1 * S1
d = d_numerator / d_denominator

b1 = (A0 - S1 * d) / S0

c = 0.0
for j in range(n):
    term = b1 + j * d - a[j]
    c += term ** 2

print("{0:.12f} {1:.12f}".format(b1, d))
print("{0:.12f}".format(c))