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

n = int(input())

print(ceil((n*n)/2))

line = "c."*int(ceil(n/2))

i = 0
while i < n:
    if i % 2 == 0:
        print([line, line[:n]][n % 2 == 1])
    else:
        print([line[::-1], line[::-1][:n]][n % 2 == 1])
    i += 1
