a-a a-b a-c aaa aab aac aaf aan aao aar aas aau ab- aba abb abc abf abn abo abr abs abu ac- aca acb acc acf acn aco acr acs acu af- afa afb afc aff afn afo afr afs afu an- ana anb anc anf ann ano anr ans anu aoa aob aoc aof aon aoo aor aos aou ar- ara arb arc arf arn aro arr ars aru as- asa asb asc asf asn aso asr ass asu au- aua aub auc auf aun auo aur aus b-u baa bab bac baf ban bao bar bas bau bba bbb bbc bbf bbn bbo bbr bbs bbu bca bcb bcc bcf bcn bco bcr bcs bcu bfa bfb bfc bff bfn bfo bfr bfs bfu bna bnb bnc bnf bnn bno bnr bns bnu boa bob boc bof bon boo bor bos bou bra brb brf brn bro brr brs bru bsa bsb bsc bsf bsn bso bsr bss bsu bua bub buc buf bun buo bur bus buu c-- caa cab cac caf can cao car cas cau cba cbb cbc cbf cbn cbo cbr cbs cbu cca ccb ccc ccf ccn cco ccr ccs ccu cfa cfb cfc cff cfn cfo cfr cfs cfu cn- cna cnb cnc cnf cnn cno cnr cns cnu co- coa cob coc cof con coo cor cos cou cra crb crc crf crn cro crr crs cru csa csb csc csf csn cso csr css csu cua cub cuc cuf cun cuo cur cus cuu faa fab fac faf fan fao far fas fau fba fbb fbc fbf fbn fbo fbr fbs fbu fca fcb fcc fcf fcn fco fcr fcs fcu ffa ffc fff ffn ffo ffr ffs ffu fna fnb fnc fnf fnn fnr fns fnu foa fob foc fof fon foo for fos fou fra frb frc frf frn fro frr frs fru fsa fsb fsc fsf fsn fso fsr fss fsu fua fub fuf fun fuo fur fus fuu naa nab nac naf nan nao nar nas nau nba nbb nbc nbf nbn nbo nbr nbs nbu nca ncb ncc ncf ncn nco ncr ncs ncu nfa nfb nfc nff nfn nfo nfr nfs nfu nna nnb nnc nnf nnn nno nns nnu no- noa nob noc nof non noo nor nos nou nra nrb nrc nrf nrn nro nrr nrs nru nsa nsb nsc nsf nsn nso nsr nss nsu nua nub nuc nun nuo nur nus nuu oaa oab oac oaf oan oao oar oas oau ob- oba obb obc obf obn obo obr obs obu oc- oca ocb occ ocf ocn oco ocr ocs ocu of- ofa ofb ofc off ofn ofo ofr ofs ofu on- ona onb onc onf onn ono onr ons onu oo- ooa oob ooc oof oon ooo oor oos or- ora orb orc orf orn oro orr ors oru os- osa osb osc osf osn oso osr oss osu ou- oua ouc ouf oun ouo our ous ra- raa rab rac raf ran rao rar ras rau rba rbb rbc rbf rbn rbo rbr rbs rbu rca rcb rcc rcf rcn rco rcr rcs rcu rfa rfb rfc rff rfn rfo rfr rfs rfu rna rnb rnc rnn rno rnr rns rnu roa rob roc rof ron roo ror ros rou rra rrb rrc rrf rrn rrr rrs rru rsa rsb rsc rsf rsn rso rsr rss rsu rua rub ruc ruf run ruo rur rus ruu saa sab sac saf san sao sar sas sau sba sbb sbc sbf sbn sbo sbr sbs sbu sca scb scc scf scn sco scr scs scu sfa sfb sfc sff sfn sfo sfr sfs sfu sna snb snc snf snn sno snr sns snu soa sob soc sof son soo sor sos sou sr- sra srb src srf srn sro srr srs ss- ssa ssb ssc ssf ssn sso ssr sss ssu sua sub suc suf sun suo sur sus suu ua- uaa uab uac uaf uan uao uar uas uau uba ubb ubc ubf ubn ubo ubr ubs ubu uca ucb ucc ucf ucn uco ucr ucs ucu ufa ufc uff ufn ufo ufr ufs ufu un- una unb unc unf unn uno unr uns unu uoa uob uoc uon uoo uor uos ur- ura urb urc urf urn uro urr urs uru usa usb usc usf usn uso usr uss usu uua uuc uun uur uus uuu