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 math import *
n = int(input())
print(ceil(n**2/2))
for i in range(n):
    if i%2: flip = '.'
    else: flip = 'C'
    for j in range(n):
        print(flip, end='')
        if flip=='C': flip = '.'
        else: flip = 'C'
    print()
