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

n = int(input())

print(str(math.ceil(n / 2) * math.ceil(n / 2) + math.floor(n / 2) * math.floor(n / 2)))

start = True
for i in range(n):
    current = start
    for j in range(n):
        if current:
            print("C", end="")
        else:
            print(".", end="")
        current = not current
    print()
    start = not start
