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).
from sys import stdin, stdout
def read():
	return stdin.readline().rstrip()

def read_int():
	return int(read())
 
def read_ints():
	return list(map(int, read().split()))
 
def solve():
	n=read_int()
	a="C."*n
	print((n*n)//2 + (n%2))
	for i in range(n):
		print(a[i%2:(i%2)+n])

solve()
