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).
#include <cstdio>
int main(){
int n; scanf("%d", &n);
printf("%d\n", (n*n+1)/2);
for (int i=0; i<n; i++){
for (int j=0; j<n; j++){
if ((i+j)&1) printf(".");
else printf("C");
}
printf("\n");
}
}