a-a a-b aaa aab aak aan aao aas aau ab- aba abb abk abn abo abs abu aka akb akk akn ako aks aku an- ana anb ank ann ano ans anu aoa aob aok aon aoo aos aou as- asa asb ask asn aso ass asu au- aua aub auk aun auo aus b-u baa bab bak ban bao bas bau bba bbb bbk bbn bbo bbs bbu bka bkb bkk bkn bko bks bna bnb bnk bnn bno bns bnu boa bob bok bon boo bos bou bsa bsb bsk bsn bso bss bsu bua bub buk bun buo bus buu ka- kaa kab kak kan kao kas kau kba kbb kbk kbn kbo kbs kbu kkb kkk kkn kks kku kn- kna knk knn kno knu koa kob kok kon koo kos kou ksa ksb ksk ksn kso kss ksu kub kuk kun kus kuu naa nab nak nan nao nas nau nba nbb nbk nbn nbo nbs nbu nka nkk nkn nko nks nku nna nnb nnk nnn nno nns nnu no- noa nob nok non noo nos nou nsa nsb nsk nsn nso nss nsu nua nub nuk nun nuo nus nuu oaa oab oak oan oao oas oau ob- oba obb obk obn obo obs obu oka okb okk oko oks oku on- ona onb onk onn ono ons onu oo- ooa oob ook oon ooo oos os- osa osb osk osn oso oss osu ou- oua ouk oun ouo ous saa sab sak san sao sas sau sba sbb sbk sbn sbo sbs sbu sk- ska skb skk sko sks sku sna snb snk snn sno sns snu soa sob sok son soo sos sou ss- ssa ssb ssk ssn sso sss ssu sua sub suk sun suo sus suu ua- uaa uab uak uan uao uas uau uba ubb ubk ubn ubo ubs ubu uka ukb ukk ukn uku un- una unb unk unn uno uns unu uoa uob uok uon uoo uos usa usb usk usn uso uss usu uua uun uus uuu