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 math

def ost(a,b):
    if a%b!=0:
        return 1
    return 0

n=int(input())

print(n**2//2+ost(n,2))
for i in range(n):
    for j in range(n):
       # print(i*n+j)
        if (i+j)%2==0:
            print("C",end='')
        else:
            print(".",end='')
    print()