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).
import sys

n = int(sys.stdin.readline())

if(n % 2 == 0):
    print(int((n ** 2) / 2))
    
    t = []
    for i in range(n):
        if(i % 2 == 0):
            t.append("C");
        else:
            t.append(".");
    a = "".join(t)
    b = a[::-1]
    for i in range(n):
        if(i % 2 == 0):
            print(a)
        else:
            print(b) 
    
else:
    i = (int(n / 2) + 1 ) ** 2
    j = int(n / 2) ** 2
    
    a = ".".join(["C" for x in range((n / 2) + 1 )])
    b = "C".join(["." for x in range(int(n / 2 + 1))])
    
    print(i + j)
    for i in range(n):
        if(i % 2 == 0):
            print(a)
        else:
            print(b)            
   