nkn nko nks nna nnb nnc nne nnf nng nnh nnk nnn nno nns no- noa nob noc noe nof nog noh nok non noo nos nsa nsb nsc nse nsf nsg nsh nsk nsn nso nss oaa oab oac oae oaf oag oah oak oan oao oas ob- oba obb obc obe obf obg obh obk obn obo obs oc- oca ocb occ ocf ocg och ock ocn oco ocs oea oeb oec oee oef oeg oeh oen oeo oes of- ofa ofb ofc ofe off ofg ofn ofo ofs oga ogc oge ogf ogg ogh ogn ogo ogs oha ohc ohe ohf ohg ohh ohn oho ohs oka okb okc oke okg okk oko oks on- ona onb onc one onf ong onh onk onn ono ons oo- ooa oob ooc oof oog ooh ook oon ooo oos os- osa osb osc ose osf osg osh osk osn oso oss saa sab sac sae saf sag sah sak san sao sas sba sbb sbc sbe sbf sbg sbh sbk sbn sbo sbs sca scb scc sce scf scg sch sck scn sco scs se- sea seb sec see sef seg seh sek sen seo ses sfa sfb sfc sfe sff sfg sfh sfk sfn sfo sfs sga sgb sgc sge sgf sgg sgh sgk sgn sgo sgs sh- sha shb shc she shf shg shh shk shn sho shs sk- ska skb skc ske skf skg skh skk sko sks sna snb snc sne snf sng snk snn sno sns soa sob soc soe sof sog soh sok son soo sos ss- ssa ssb ssc sse ssf ssg ssh ssk ssn sso sss