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).
def answer():
    a = int(input())
    print(int((a**2)/2)+a%2)
    i=1
    while i<=a:
        j=1
        c_out=""
        
        while j<=a:
            if j%2==i%2:
                start="C"
            else:
                start="."
            c_out+=start
            j+=1
        print(c_out)
        i+=1
answer()