old olk oll oln olo ols on- ona onb onc ond onh onk onl onn ono onr ons oo- ooa oob ooc ood ooh ook ool oon ooo oor oos or- ora orb orc ord orh ork orl orn oro orr ors os- osa osb osc osd osh osk osl osn oso osr oss ra- raa rab rac rad rah rak ral ran rao rar ras rba rbb rbc rbd rbh rbk rbl rbn rbo rbr rbs rca rcb rcc rcd rch rcl rcn rco rcr rcs rda rdb rdc rdd rdh rdl rdn rdo rdr rds rh- rha rhb rhc rhd rhh rhl rhn rho rhr rhs rkb rkc rkk rko rks rla rlc rld rlh rll rln rlo rlr rls rna rnb rnc rnd rnh rnn rno rnr rns roa rob roc rod roh rok rol ron roo ror ros rra rrb rrc rrd rrh rrk rrl rrn rrr rrs rsa rsb rsc rsd rsh rsk rsl rsn rso rsr rss saa sab sac sad sah sak sal san sao sar sas sba sbb sbc sbd sbh sbk sbl sbn sbo sbr sbs sca scb scc scd sch sck scl scn sco scr scs sda sdb sdc sdd sdh sdk sdl sdn sdo sdr sds sh- sha shb shc shd shh shk shl shn sho shr shs sk- ska skb skc skd skh skk skl sko skr sks sla slb slc sld slh slk sll sln slo slr sls sna snb snc snd snk snl snn sno snr sns soa sob soc sod soh sok sol son soo sor sos sr- sra srb src srd srh srk srl srn sro srr srs ss- ssa ssb ssc ssd ssh ssk ssl ssn sso ssr sss