use feature 'state';
use Math::Fleximal;
sub getnext {
	state $num = Math::Fleximal->new("A",
		[qw/A B C D F G H J K L M N P Q R S T V X Y Z/]);
	do { $num=$num->add("B") }
		until $num->to_str!~/A/;
	return $num->to_str;
}
print getnext."\n" for 1 .. 1000;
__END__
B
C
D
...
Y
Z
BB
BC
BD
...
ZY
ZZ
BBB
BBC
...