a-a aaa aaf aam aan aao af- afa aff afm afn afo ama amf amm amn amo an- ana anf anm ann ano aoa aof aom aon aoo faa faf fam fan fao ffa fff ffm ffn ffo fma fmf fmm fmn fmo fna fnf fnm fnn foa fof fom fon foo m-f m-o maa maf mam man mao mfa mff mfm mfn mfo mma mmf mmm mmn mmo mna mnf mnm mnn mno moa mof mom mon moo naa naf nam nan nao nfa nff nfn nfo nma nmm nmn nmo nna nnf nnm nnn nno no- noa nof nom non noo oaa oaf oam oan oao of- ofa off ofm ofn ofo om- oma omf omm omn omo on- ona onf onn ono oo- ooa oof oom oon ooo