a-a a-c aaa aac aak aao aas aav ac- aca acc ack aco acs acv aka akc akk ako aks akv aoa aoc aok aoo aos aov as- asa asc ask aso ass asv av- ava avc avk avo avs c-- caa cac cak cao cas cav cca ccc cck cco ccs ccv cka ckc cko cks co- coa coc cok coo cos cov csa csc csk cso css csv cva cvc cvk cvo cvs cvv ka- kaa kac kak kao kas kav kca kcc kck kcs kkc kkk kks kkv koa koc kok koo kos ksa ksc ksk kso kss ksv kva kvk kvo kvs kvv oaa oac oak oao oas oav oc- oca occ ock oco ocs ocv oka okc okk oko oks oo- ooa ooc ook ooo oos oov os- osa osc osk oso oss osv ov- ova ovc ovo ovs ovv saa sac sak sao sas sav sca scc sck sco scs scv sk- ska skc skk sko sks soa soc sok soo sos sov ss- ssa ssc ssk sso sss ssv sva svc svk svo svs svv v-a vaa vac vak vao vas vav vca vcc vco vcs vka voa voc vok voo vos vov vsa vsc vsk vso vss vsv vva vvc vvo vvs vvv