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(n+2*(n-2))
c = 0
for i in range(n):
  if i % 2 == 0:
    if n % 2 == 0:
      print(('C.'*(math.ceil(n / 2))))
    else:
      print(('C.'*(math.ceil(n / 2)))[:-1])
  else:
    if n % 2 == 0:
      print(('.C'*(math.ceil(n / 2))))
    else:
      print(('.C'*(math.ceil(n / 2)))[:-1])
