a-a aaa aad aan aao aap ad- ada add adn ado adp an- ana and ann ano anp aoa aod aon aoo aop ap- apa apd apn apo app daa dad dan dao dap dda ddd ddn ddo ddp dna dnd dnn dno dnp doa dod don doo dop dpa dpd dpn dpo dpp naa nad nan nao nap nda ndd ndn ndo ndp nna nnn nno nnp no- noa nod non noo nop npa npd npn npo npp oaa oad oan oao oap oda odd odn odo odp on- ona ond onn ono onp oo- ooa ood oon ooo oop op- opa opd opn opo opp p-p paa pad pan pao pap pda pdd pdn pdo pdp pn- pna pnd pnn pno pnp poa pod pon poo pop ppa ppd ppn ppo ppp