a-a a-b a-c aaa aab aac aaf aak aan aao aas aau ab- aba abb abc abf abk abn abo abs abu ac- aca acb acc acf ack acn aco acs acu af- afa afb afc aff afk afn afo afs afu aka akb akc akk akn ako aks aku an- ana anb anc anf ank ann ano ans anu aoa aob aoc aof aok aon aoo aos aou as- asa asb asc asf ask asn aso ass asu au- aua aub auc auf auk aun auo aus b-u baa bab bac baf bak ban bao bas bau bba bbb bbc bbf bbk bbn bbo bbs bbu bca bcb bcc bcf bck bcn bco bcs bcu bfa bfb bfc bff bfn bfo bfs bfu bka bkb bkc bkf bkk bkn bko bks bna bnb bnc bnf bnk bnn bno bns bnu boa bob boc bof bok bon boo bos bou bsa bsb bsc bsf bsk bsn bso bss bsu bua bub buc buf buk bun buo bus buu c-- caa cab cac caf cak can cao cas cau cba cbb cbc cbf cbk cbn cbo cbs cbu cca ccb ccc ccf cck ccn cco ccs ccu cfa cfb cfc cff cfk cfn cfo cfs cfu cka ckb ckc cko cks cn- cna cnb cnc cnf cnn cno cns cnu co- coa cob coc cof cok con coo cos cou csa csb csc csf csk csn cso css csu cua cub cuc cuf cuk cun cuo cus cuu faa fab fac faf fak fan fao fas fau fba fbb fbc fbf fbk fbn fbo fbs fbu fca fcb fcc fcf fck fcn fco fcs fcu ffa ffc fff ffk ffn ffo ffs ffu fka fkb fkc fkf fkk fna fnb fnc fnf fnk fnn fns fnu foa fob foc fof fok fon foo fos fou fsa fsb fsc fsf fsk fsn fso fss fsu fua fub fuf fuk fun fuo fus fuu ka- kaa kab kac kaf kak kan kao kas kau kba kbb kbc kbf kbk kbn kbo kbs kbu kca kcb kcc kck kcn kcs kcu kfa kfc kff kfo kfs kfu kkb kkc kkk kkn kks kku kn- kna knc knf knk knn kno knu koa kob koc kof kok kon koo kos kou ksa ksb ksc ksf ksk ksn kso kss ksu kub kuc kuk kun kus kuu naa nab nac naf nak nan nao nas nau nba nbb nbc nbf nbk nbn nbo nbs nbu nca ncb ncc ncf nck ncn nco ncs ncu nfa nfb nfc nff nfk nfn nfo nfs nfu nka nkc nkf nkk nkn nko nks nku nna nnb nnc nnf nnk nnn nno nns nnu no- noa nob noc nof nok non noo nos nou nsa nsb nsc nsf nsk nsn nso nss nsu nua nub nuc nuk nun nuo nus nuu oaa oab oac oaf oak oan oao oas oau ob- oba obb obc obf obk obn obo obs obu oc- oca ocb occ ocf ock ocn oco ocs ocu of- ofa ofb ofc off ofn ofo ofs ofu oka okb okc okk oko oks oku on- ona onb onc onf onk onn ono ons onu oo- ooa oob ooc oof ook oon ooo oos os- osa osb osc osf osk osn oso oss osu ou- oua ouc ouf ouk oun ouo ous saa sab sac saf sak san sao sas sau sba sbb sbc sbf sbk sbn sbo sbs sbu sca scb scc scf sck scn sco scs scu sfa sfb sfc sff sfk sfn sfo sfs sfu sk- ska skb skc skf skk sko sks sku sna snb snc snf snk snn sno sns snu soa sob soc sof sok son soo sos sou ss- ssa ssb ssc ssf ssk ssn sso sss ssu sua sub suc suf suk sun suo sus suu ua- uaa uab uac uaf uak uan uao uas uau uba ubb ubc ubf ubk ubn ubo ubs ubu uca ucb ucc ucf uck ucn uco ucs ucu ufa ufc uff ufn ufo ufs ufu uka ukb ukc ukf ukk ukn uku un- una unb unc unf unk unn uno uns unu uoa uob uoc uok uon uoo uos usa usb usc usf usk usn uso uss usu uua uuc uun uus uuu