-ic a-a a-b a-c a-i aaa aab aac aai aak aan aao aar ab- aba abb abc abi abk abn abo abr ac- aca acb acc aci ack acn aco acr ai- aia aib aic aii aik ain aio air aka akb akc aki akk akn ako akr an- ana anb anc ani ank ann ano anr aoa aob aoc aoi aok aon aoo aor ar- ara arb arc ari ark arn aro arr baa bab bac bai bak ban bao bar bba bbb bbc bbi bbk bbn bbo bbr bca bcb bcc bci bck bcn bco bcr bi- bia bib bic bii bik bin bio bir bka bkb bkc bkk bkn bko bkr bna bnb bnc bni bnk bnn bno bnr boa bob boc boi bok bon boo bor bra brb bri brk brn bro brr c-- caa cab cac cai cak can cao car cba cbb cbc cbi cbk cbn cbo cbr cca ccb ccc cci cck ccn cco ccr ci- cia cib cic cii cik cin cio cir cka ckb ckc cki cko cn- cna cnb cnc cni cnn cno cnr co- coa cob coc coi cok con coo cor cra crb crc cri crk crn cro crr ia- iaa iab iac iai ian iao iar iba ibb ibc ibi ibk ibn ibo ibr ica icb icc ici ick icn ico icr iia iib iic iii iin iio iir ika ikb ikc iki ikk iko ikr in- ina inb inc ini ink inn ino inr io- ioa iob ioc ioi ion ioo ior ir- ira irb irc iri irk irn iro irr ka- kaa kab kac kai kak kan kao kar kba kbb kbc kbi kbk kbn kbo kbr kca kcb kcc kci kck kcn kcr kia kib kic kii kik kin kio kir kkb kkc kki kkk kkn kkr kn- kna knc kni knk knn kno knr koa kob koc koi kok kon koo kor kra krc kri krk krn kro krr n-i naa nab nac nai nak nan nao nar nba nbb nbc nbi nbk nbn nbo nbr nca ncb ncc nci nck ncn nco ncr nia nib nic nii nik nin nio nir nka nkc nki nkk nkn nko nkr nna nnb nnc nni nnk nnn nno no- noa nob noc noi nok non noo nor nra nrb nrc nri nrk nrn nro nrr o-i oaa oab oac oai oak oan oao oar ob- oba obb obc obi obk obn obo obr oc- oca ocb occ oci ock ocn oco ocr oia oib oic oii oik oin oio oir oka okb okc oki okk oko okr on- ona onb onc oni onk onn ono onr oo- ooa oob ooc ooi ook oon ooo oor or- ora orb orc ori ork orn oro orr ra- raa rab rac rai rak ran rao rar rba rbb rbc rbi rbk rbn rbo rbr rca rcb rcc rci rcn rco rcr ria rib ric rii rik rin rio rir rkb rkc rkk rko rna rnb rnc rni rnn rno rnr roa rob roc roi rok ron roo ror rra rrb rrc rri rrk rrn rrr