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

def solution():
    number = int(input())
    if number % 2 == 0:
        print(number*number//2)
    else:
        print(number*number//2 + 1)
    for i in range(number):
        row = ""
        if i % 2 == 0:
            first = 'C'
            second = '.'
        else:
            first = '.'
            second = 'C'
        for j in range(number):
            if j % 2 == 0:
                row += first
            else:
                row += second
        print(row)


if __name__ == "__main__":
    solution()