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())
coders = math.ceil(n*n/2)

shift = 0
toggle = True
line = ""
print(coders)
for i in range(n):
    if not shift :
        for j in range(n):
            if toggle:
                line = line + 'C'
                toggle = False
            else:
                line = line + '.'
                toggle = True
    else:
        for j in range(n):
            if not toggle:
                line = line + 'C'
                toggle = True
            else :
                line = line + '.'
                toggle = False
    print(line)
    line =""
    shift = (shift+1)%2
    toggle = True
