Iahub likes chess very much. He even invented a new chess piece named Coder. A Coder can move (and attack) one square horizontally or vertically. More precisely, if the Coder is located at position (*x*, *y*), he can move to (or attack) positions (*x* + 1, *y*), (*x*–1, *y*), (*x*, *y* + 1) and (*x*, *y*–1).

Iahub wants to know how many Coders can be placed on an *n* × *n* chessboard, so that no Coder attacks any other Coder.
The first line contains an integer *n* (1 ≤ *n* ≤ 1000).
#==========3 задание===============
import math

n = int(input())

r1 = math.ceil(n/2)
r2 = math.floor(n/2)
r3 = r1*r1 + r2*r2

print(r3)
l  = []
l1 = ["C." for i in range(n)]
l2 = [".C" for i in range(n)]
for i in range(n):
    l += ["".join(l1)[:n]]
    l += ["".join(l2)[:n]]
l = l[:n]
for i in l:
    print(i)
