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 ceil

def coder():
    t = int(input())
    
    num = ceil(t ** 2 / 2)
    print(num)
    
    lst = ["C", "."]
    lst = lst * t
    
    for i in range(1, t + 1):
        if i % 2 != 0:
            print(*lst[:t], sep=(" "))
            
        else:
            print(*lst[1: t + 1], sep=(" "))
        
        
        
coder()