a-a a-c aaa aac aaf aah aao aas ac- aca acc acf ach aco acs af- afa afc aff afh afo afs aha ahc ahf ahh aho ahs aoa aoc aof aoh aoo aos as- asa asc asf ash aso ass c-- caa cac caf cah cao cas cca ccc ccf cch cco ccs cfa cfc cff cfh cfo cfs ch- cha chc chf chh cho chs co- coa coc cof coh coo cos csa csc csf csh cso css faa fac faf fah fao fas fca fcc fcf fco fcs ffa ffc fff ffh ffo ffs fha fhc fhf fhh fho fhs foa foc fof foh foo fos fsa fsc fsf fsh fso fss haa hac haf hah hao has hca hcc hcf hch hco hcs hfa hfc hff hfh hfo hfs hha hhc hhf hhh hho hhs hoa hoc hof hoh hoo hos hsa hsc hsf hsh hss oaa oac oaf oah oao oas oc- oca occ ocf och oco ocs of- ofa ofc off ofo ofs oha ohc ohf ohh oho ohs oo- ooa ooc oof ooh ooo oos os- osa osc osf osh oso oss saa sac saf sah sao sas sca scc scf sch sco scs sfa sfc sff sfh sfo sfs sh- sha shc shf shh sho shs soa soc sof soh soo sos ss- ssa ssc ssf ssh sso sss