a-a a-b a-c aaa aab aac aaf aah aan aao aar ab- aba abb abc abf abh abn abo abr ac- aca acb acc acf ach acn aco acr af- afa afb afc aff afh afn afo afr aha ahb ahc ahf ahh ahn aho ahr an- ana anb anc anf anh ann ano anr aoa aob aoc aof aoh aon aoo aor ar- ara arb arc arf arh arn aro arr baa bab bac baf bah ban bao bar bba bbb bbc bbf bbh bbn bbo bbr bca bcb bcc bcf bch bcn bco bcr bfa bfb bfc bff bfh bfn bfo bfr bha bhb bhc bhf bhh bho bhr bna bnb bnc bnf bnn bno bnr boa bob boc bof boh bon boo bor bra brb brf brh brn bro brr c-- caa cab cac caf cah can cao car cba cbb cbc cbf cbh cbn cbo cbr cca ccb ccc ccf cch ccn cco ccr cfa cfb cfc cff cfh cfn cfo cfr ch- cha chb chc chf chh chn cho chr cn- cna cnb cnc cnf cnh cnn cno cnr co- coa cob coc cof coh con coo cor cra crb crc crf crh crn cro crr faa fab fac faf fah fan fao far fba fbb fbc fbf fbh fbn fbo fbr fca fcb fcc fcf fcn fco fcr ffa ffc fff ffh ffn ffo ffr fha fhb fhc fhf fhh fhn fho fhr fna fnb fnc fnf fnh fnn fnr foa fob foc fof foh fon foo for fra frb frc frf frh frn fro frr haa hab hac haf hah han hao har hba hbb hbc hbf hbh hbn hbo hbr hca hcb hcc hcf hch hcn hco hcr hfa hfb hfc hff hfh hfn hfo hfr hha hhb hhc hhf hhh hhn hho hhr hna hnb hnc hnf hnh hnn hno hoa hob hoc hof hoh hon hoo hor hr- hra hrb hrc hrf hrh hrn hro hrr naa nab nac naf nah nan nao nar nba nbb nbc nbf nbn nbo nbr nca ncb ncc ncf nch ncn nco ncr nfa nfb nfc nff nfn nfo nfr nha nhb nhc nhf nhh nhn nhr nna nnb nnc nnf nnh nnn nno no- noa nob noc nof noh non noo nor nra nrb nrc nrf nrn nro nrr oaa oab oac oaf oah oan oao oar ob- oba obb obc obf obh obn obo obr oc- oca ocb occ ocf och ocn oco ocr of- ofa ofb ofc off ofn ofo ofr oha ohc ohf ohh ohn oho ohr on- ona onb onc onf onh onn ono onr oo- ooa oob ooc oof ooh oon ooo oor or- ora orb orc orf orh orn oro orr ra- raa rab rac raf rah ran rao rar rba rbb rbc rbf rbh rbn rbo rbr rca rcb rcc rcf rch rcn rco rcr rfa rfb rfc rff rfh rfn rfo rfr rh- rha rhb rhc rhf rhh rhn rho rhr rna rnb rnc rnh rnn rno rnr roa rob roc rof roh ron roo ror rra rrb rrc rrf rrh rrn rrr