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).
import math

if __name__ == '__main__':
	n = int(input())

	print(math.ceil(n ** 2 / 2))

	for i in range(n):
		if i % 2 == 0:
			for j in range(n):
				if j % 2 == 0: print('C', end = '')
				else: print('.', end = '')
			print()
		else:
			for j  in range(n):
				if j % 2 == 0: print('.', end = '')
				else: print('C', end = '')
			print() 
