-er -ic bbb bbc bbe bbi bbk bbr bbt bcb bcc bce bci bck bcr bct be- beb bec bee bei bek ber bet bi- bib bic bie bii bik bir bit bkb bkc bke bkk bkr bkt brb bre bri brk brr brt btb btc bte bti btk btr btt c-- cbb cbc cbe cbi cbk cbr cbt ccb ccc cce cci cck ccr cct ce- ceb cec cee cei cek cer cet ci- cib cic cie cii cik cir cit ckb ckc cki ckt crb crc cre cri crk crr crt ctb ctc cte cti ctk ctr ctt ebb ebc ebe ebi ebk ebr ebt ec- ecb ecc ece eci eck ecr ect eeb eec eee eek eer eet eib eic eie eii eik eir eit ekb ekc eke eki ekr ekt erb erc ere eri erk err ert etb etc ete eti etk etr ett ibb ibc ibe ibi ibk ibr ibt icb icc ice ici ick icr ict ie- iec iee iei iek ier iet iib iic iie iii iir iit ikb ikc ike iki ikk ikr ikt ir- irb irc ire iri irk irr irt itb itc ite iti itk itt k-t kbb kbc kbe kbi kbk kbr kcb kcc kce kci kck kcr kct ke- keb kec kee kei kek ker ket kib kic kie kii kik kir kit kkb kkc kke kki kkk kkr kkt krc kri krk krr krt ktb ktc kte ktk ktr ktt rbb rbc rbe rbi rbk rbr rbt rcb rcc rce rci rcr rct re- reb rec ree rei rek rer ret rib ric rie rii rik rir rit rkb rkc rke rkk rkt rrb rrc rri rrk rrr rrt rtb rtc rte rti rtk rtr rtt tbb tbc tbe tbi tbk tbr tbt tcb tcc tce tci tck tcr tct te- teb tec tee tei tek ter tet tib tic tie tii tik tir tit tkb tkc tke tkk tkr tkt trb trc tre tri trk trr trt ttb ttc tte tti ttk ttr ttt