A9317. Coder

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 $n$ $(1<=n<=1000)$ .

On the first line print an integer, the maximum number of Coders that can be placed on the chessboard.

On each of the next $n$ lines print $n$ characters, describing the configuration of the Coders. For an empty cell print an '.', and for a Coder print a 'C'.

If there are multiple correct answers, you can print any.