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).
n = int(input())
if n == 1:
    print(1)
    print('c')
    exit()
a = ['c' for i in range(n)]
b = a[:]
for i in range(1, n, 2):
    a[i] = '.'
for i in range(0, n, 2):
    b[i] = '.'
if n%2 == 0:
    print(n)
else: print(n + 1) 
flag = True
for i in range(n):
    if flag == True:
        print(*a, sep='')
        flag = False
    else:
        print(*b, sep='')
        flag = True
