-ic a-a a-b a-c a-i aaa aab aac aai aak aan aao ab- aba abb abc abi abk abn abo ac- aca acb acc aci ack acn aco ai- aia aib aic aii aik ain aio aka akb akc aki akk akn ako an- ana anb anc ani ank ann ano aoa aob aoc aoi aok aon aoo baa bab bac bai bak ban bao bba bbb bbc bbi bbk bbn bbo bca bcb bcc bci bck bcn bco bi- bia bib bic bii bik bin bio bka bkb bkc bkk bkn bko bna bnb bnc bni bnk bnn bno boa bob boc boi bok bon boo c-- caa cab cac cai cak can cao cba cbb cbc cbi cbk cbn cbo cca ccb ccc cci cck ccn cco ci- cia cib cic cii cik cin cio cka ckb ckc cki cko cn- cna cnb cnc cni cnn cno co- coa cob coc coi cok con coo ia- iaa iab iac iai ian iao iba ibb ibc ibi ibk ibn ibo ica icb icc ici ick icn ico iia iib iic iii iin iio ika ikb ikc iki ikk iko in- ina inb inc ini ink inn ino io- ioa iob ioc ioi ion ioo ka- kaa kab kac kai kak kan kao kba kbb kbc kbi kbk kbn kbo kca kcb kcc kci kck kcn kia kib kic kii kik kin kio kkb kkc kki kkk kkn kn- kna knc kni knk knn kno koa kob koc koi kok kon koo n-i naa nab nac nai nak nan nao nba nbb nbc nbi nbk nbn nbo nca ncb ncc nci nck ncn nco nia nib nic nii nik nin nio nka nkc nki nkk nkn nko nna nnb nnc nni nnk nnn nno no- noa nob noc noi nok non noo o-i oaa oab oac oai oak oan oao ob- oba obb obc obi obk obn obo oc- oca ocb occ oci ock ocn oco oia oib oic oii oik oin oio oka okb okc oki okk oko on- ona onb onc oni onk onn ono oo- ooa oob ooc ooi ook oon ooo