a-a a-b a-c aaa aab aac aam aan aao aar ab- aba abb abc abm abn abo abr ac- aca acb acc acm acn aco acr ama amb amc amm amn amo amr an- ana anb anc anm ann ano anr aoa aob aoc aom aon aoo aor ar- ara arb arc arm arn aro arr baa bab bac bam ban bao bar bba bbb bbc bbm bbn bbo bbr bca bcb bcc bcm bcn bco bcr bma bmb bmc bmm bmn bmo bmr bna bnb bnc bnn bno bnr boa bob boc bom bon boo bor bra brb brm brn bro brr c-- caa cab cac cam can cao car cba cbb cbc cbm cbn cbo cbr cca ccb ccc ccm ccn cco ccr cma cmb cmc cmm cmn cmo cmr cn- cna cnb cnc cnm cnn cno cnr co- coa cob coc com con coo cor cra crb crc crm crn cro crr m-o m-r maa mab mac mam man mao mar mba mbb mbc mbm mbo mbr mc- mca mcb mcc mcm mcn mco mcr mma mmb mmc mmm mmn mmo mmr mna mnb mnc mnm mnn mno mnr moa mob moc mom mon moo mor mra mrb mrc mrm mrn mro mrr naa nab nac nam nan nao nar nba nbb nbc nbm nbn nbo nbr nca ncb ncc ncm ncn nco ncr nma nmb nmc nmm nmn nmo nmr nna nnb nnc nnm nnn nno no- noa nob noc nom non noo nor nra nrb nrc nrm nrn nro nrr oaa oab oac oam oan oao oar ob- oba obb obc obm obn obo obr oc- oca ocb occ ocm ocn oco ocr om- oma omb omc omm omn omo omr on- ona onb onc onn ono onr oo- ooa oob ooc oom oon ooo oor or- ora orb orc orm orn oro orr ra- raa rab rac ram ran rao rar rba rbb rbc rbm rbn rbo rbr rca rcb rcc rcm rcn rco rcr rma rmb rmc rmm rmn rmo rmr rna rnb rnc rnm rnn rno rnr roa rob roc rom ron roo ror rra rrb rrc rrm rrn rrr