a-a a-c aaa aac aak aan aao aas ac- aca acc ack acn aco acs aka akc akk akn ako aks an- ana anc ank ann ano ans aoa aoc aok aon aoo aos as- asa asc ask asn aso ass c-- caa cac cak can cao cas cca ccc cck ccn cco ccs cka ckc cko cks cn- cna cnc cnn cno cns co- coa coc cok con coo cos csa csc csk csn cso css ka- kaa kac kak kan kao kas kca kcc kck kcn kcs kkc kkk kkn kks kn- kna knc knk knn kno koa koc kok kon koo kos ksa ksc ksk ksn kso kss naa nac nak nan nao nas nca ncc nck ncn nco ncs nka nkc nkk nkn nko nks nna nnc nnk nnn nno nns no- noa noc nok non noo nos nsa nsc nsk nsn nso nss oaa oac oak oan oao oas oc- oca occ ock ocn oco ocs oka okc okk oko oks on- ona onc onk onn ono ons oo- ooa ooc ook oon ooo oos os- osa osc osk osn oso oss saa sac sak san sao sas sca scc sck scn sco scs sk- ska skc skk sko sks sna snc snk snn sno sns soa soc sok son soo sos ss- ssa ssc ssk ssn sso sss