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).
'''
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'''
import sys
input = lambda : sys.stdin.readline().strip()
def ii():
    return int(input())
def lii():
    return list(map(int, input().split()))
def ss():
    return input()
def lss():
    return list(map(str, input().split()))
def yes():
    print("YES")
def no():
    print("NO")
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n = int(input())
s = (n*n+1)//2
print(s)
for i in range(n):
    print(('C.'*n)[i:i+n])
        