a-a aaa aan aao aap aar aax an- ana ann ano anp anr anx aoa aon aoo aop aor aox ap- apa apn apo app apr apx ar- ara arn aro arp arr arx ax- axa axn axo axp axr axx naa nan nao nap nar nax nna nnn nno nnp no- noa non noo nop nor nox npa npn npo npp npr nra nrn nro nrp nrr nrx oaa oan oao oap oar oax on- ona onn ono onp onr onx oo- ooa oon ooo oop oor oox op- opa opn opo opp opr opx or- ora orn oro orp orr orx ox- oxa oxn oxo oxx p-p paa pan pao pap par pax pn- pna pnn pno pnp pnr pnx poa pon poo pop por pox ppa ppn ppo ppp ppr ppx pra prn pro prp prr prx pxr ra- raa ran rao rap rar rax rna rnn rno rnp rnr roa ron roo rop ror rox rpa rpn rpo rpp rpr rpx rra rrn rrp rrr rxp rxr xaa xan xap xar xna xno xoa xon xoo xop xor xox xpa xpn xpo xpp xrx xxo xxp xxx