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())
count=0
if n%2==0:
    print(n*n//2)
    for i in range(0,n):
        if i%2==0:
            for g in range(0,n,2):
                print("c.", end="")
            print()
        else:
            for a in range(0,n,2):
                print(".c",end="")
            print()
else:
    print(n*n//2+1)
    for j in range(0,n):
        if j%2==0:
            for h in range(1,n,2):
                print("c.", end="")
            print()
        else:
            for m in range(1,n,2):
                print(".c",end="")
            print()