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).
#!/usr/bin/python3
# -*- coding: <utf-8> -*-

import itertools as ittls
from collections import Counter

import string


def sqr(x):
    return x*x

def inputarray(func = int):
    return map(func, input().split())

# -------------------------------
# -------------------------------

N = int(input())
print( (sqr(N) + 1)//2 )

for i in range(N):
    if i&1:
        s = '.x'*(N//2)
        if N&1:
            s = s + '.'
    else:
        s = 'x.'*(N//2)
        if N&1:
            s = s + 'x'

    print(s)

