a-a a-b a-c aaa aab aac aaf aah aan aar ab- aba abb abc abf abh abn abr ac- aca acb acc acf ach acn acr af- afa afb afc aff afh afn afr aha ahb ahc ahf ahh ahn ahr an- ana anb anc anf anh ann anr ar- ara arb arc arf arh arn arr baa bab bac baf bah ban bar bba bbb bbc bbf bbh bbn bbr bca bcb bcc bcf bch bcn bcr bfa bfb bfc bff bfh bfn bfr bha bhb bhc bhf bhh bhr bna bnb bnc bnf bnn bnr bra brb brf brh brn brr c-- caa cab cac caf cah can car cba cbb cbc cbf cbh cbn cbr cca ccb ccc ccf cch ccn ccr cfa cfb cfc cff cfh cfn cfr ch- cha chb chc chf chh chn chr cn- cna cnb cnc cnf cnh cnn cnr cra crb crc crf crh crn crr faa fab fac faf fah fan far fba fbb fbc fbf fbh fbn fbr fca fcb fcc fcf fcn fcr ffa ffc fff ffh ffn ffr fha fhb fhc fhf fhh fhn fhr fna fnb fnc fnf fnh fnn fnr fra frb frc frf frh frn frr haa hab hac haf hah han har hba hbb hbc hbf hbh hbn hbr hca hcb hcc hcf hch hcn hcr hfa hfb hfc hff hfh hfn hfr hha hhb hhc hhf hhh hhn hhr hna hnb hnc hnf hnh hnn hr- hra hrb hrc hrf hrh hrn hrr naa nab nac naf nah nan nar nba nbb nbc nbf nbn nbr nca ncb ncc ncf nch ncn ncr nfa nfb nfc nff nfn nfr nha nhb nhc nhf nhh nhn nhr nna nnb nnc nnf nnh nnn nra nrb nrc nrf nrn nrr ra- raa rab rac raf rah ran rar rba rbb rbc rbf rbh rbn rbr rca rcb rcc rcf rch rcn rcr rfa rfb rfc rff rfh rfn rfr rh- rha rhb rhc rhf rhh rhn rhr rna rnb rnc rnh rnn rnr rra rrb rrc rrf rrh rrn rrr