($N,$K)=glob<>;
$M=($N-1)/$K+1|0;
$M++while$M*$M<$N;
print$M,$/;
@A=map[('.')x$M,$/],1..$M;
for$i(0..$M-1){
	for$j(0..$M-1){
		if($N--){
			$A[$j][($i+$j)%$M]='#'
		}else{
			goto z
		}
	}
}
z:print@$_ for@A