a-a a-z aaa aao aar aas aaz aoa aoo aor aos ar- ara aro arr ars arz as- asa aso asr ass asz az- aza azo azs azz oaa oao oar oas oo- ooa ooo oor oos or- ora oro orr ors orz os- osa oso osr oss oza ozo ozs ozz ra- raa rao rar ras raz roa roo ror ros roz rra rrr rrs rsa rso rsr rss rza rzo saa sao sar sas saz soa soo sor sos soz sr- sra sro srr srs ss- ssa sso ssr sss ssz sza szr zaa zao zar zas zaz zo- zoa zoo zor zos zro zrs zsa zsz zzr zzs zzz