c-- ccc ccf cch cco ccs cfc cff cfh cfo cfs ch- chc chf chh cho chs co- coc cof coh coo cos csc csf csh cso css fcc fcf fco fcs ffc fff ffh ffo ffs fhc fhf fhh fho fhs foc fof foh foo fos fsc fsf fsh fso fss hcc hcf hch hco hcs hfc hff hfh hfo hfs hhc hhf hhh hho hhs hoc hof hoh hoo hos hsc hsf hsh hss oc- occ ocf och oco ocs of- ofc off ofo ofs ohc ohf ohh oho ohs oo- ooc oof ooh ooo oos os- osc osf osh oso oss scc scf sch sco scs sfc sff sfh sfo sfs sh- shc shf shh sho shs soc sof soh soo sos ss- ssc ssf ssh sso sss