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%2==0:
    print(n**2//2)
else:
    print((n**2+1)//2)

var="c"
f=1
for i in range(n):
    for j in range(n):
        if j==0 and i>=1:
            if var=="c":
                var="."
                f=0
            elif var==".":
                var="c"
                f=1
        if f==1:
            print("c",end="")
            f=(f+1)%2
        else:
            print(".",end="")
            f = (f + 1) % 2
    print()






