a-a a-c aaa aac aak aao aar aav ac- aca acc ack aco acr acv aka akc akk ako akr akv aoa aoc aok aoo aor aov ar- ara arc ark aro arr arv av- ava avc avk avo avr c-- caa cac cak cao car cav cca ccc cck cco ccr ccv cka ckc cko co- coa coc cok coo cor cov cra crc crk cro crr crv cva cvc cvk cvo cvr cvv ka- kaa kac kak kao kar kav kca kcc kck kcr kkc kkk kkr kkv koa koc kok koo kor kra krc krk kro krr krv kva kvk kvo kvr kvv oaa oac oak oao oar oav oc- oca occ ock oco ocr ocv oka okc okk oko okr oo- ooa ooc ook ooo oor oov or- ora orc ork oro orr orv ov- ova ovc ovo ovv ra- raa rac rak rao rar rav rca rcc rco rcr rcv rkc rkk rko rkv roa roc rok roo ror rov rra rrc rrk rrr rva rvc rvo rvr rvv v-a vaa vac vak vao var vav vca vcc vco vcr vka voa voc vok voo vor vov vra vrc vrk vrr vva vvc vvo vvr vvv