-ic bbb bbc bbe bbi bbk bbo bbt bcb bcc bce bci bck bco bct be- beb bec bee bei bek beo bet bi- bib bic bie bii bik bio bit bkb bkc bke bkk bko bkt bob boc boe boi bok boo bot btb btc bte bti btk bto btt c-- cbb cbc cbe cbi cbk cbo cbt ccb ccc cce cci cck cco cct ce- ceb cec cee cei cek ceo cet ci- cib cic cie cii cik cio cit ckb ckc cki cko ckt co- cob coc coe coi cok coo cot ctb ctc cte cti ctk cto ctt ebb ebc ebe ebi ebk ebo ebt ec- ecb ecc ece eci eck eco ect eeb eec eee eek eeo eet eib eic eie eii eik eio eit ekb ekc eke eki eko ekt eo- eob eoc eoe eoi eok eoo eot etb etc ete eti etk eto ett ibb ibc ibe ibi ibk ibo ibt icb icc ice ici ick ico ict ie- iec iee iei iek iet iib iic iie iii iio iit ikb ikc ike iki ikk iko ikt io- iob ioc ioe ioi ioo iot itb itc ite iti itk ito itt k-t kbb kbc kbe kbi kbk kbo kcb kcc kce kci kck kct ke- keb kec kee kei kek keo ket kib kic kie kii kik kio kit kkb kkc kke kki kkk kkt kob koc koe koi kok koo kot ktb ktc kte ktk kto ktt o-i ob- obb obc obe obi obk obo obt oc- ocb occ oci ock oco oct oeb oec oee oei oeo oet oib oic oie oii oik oio oit okb okc oke oki okk oko oo- oob ooc ooi ook ooo oot ot- otb otc ote oti otk oto ott tbb tbc tbe tbi tbk tbo tbt tcb tcc tce tci tck tco tct te- teb tec tee tei tek teo tet tib tic tie tii tik tio tit tkb tkc tke tkk tko tkt to- tob toc toe toi tok too tot ttb ttc tte tti ttk tto ttt