N = int(input())
a = list(map(int, input().split()))
S = sum(a)
T = sum((i+1)*a[i] for i in range(N))
d = (T-(N+1)/2*S)/(N*(N+1)*(2*N+1)//6-N*(N+1)**2/4)
b = (S-N*(N+1)//2*d)/N
c = sum((b+(i+1)*d-a[i])**2 for i in range(N))
print(b+d, d)
print(c)