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 sys
# sys.stdin=open("input.in",'r')
# sys.stdout=open("outp.out",'w')
n=int(input())
if n%2==0:
	print(n*n/2)
else:
	print(int((n*n)/2)+1)	
c=True
for i in range(n):
	for j in range(n):
		if c==True:
			print('c',end=' ')
			c=False
		else:
			print(".",end=' ')	
			c=True
	print()
	c=not c 		

