-er -ic bbb bbc bbe bbi bbk bbo bbr bbs bbt bcb bcc bce bci bck bco bcr bcs bct be- beb bec bee bei bek beo ber bes bet bi- bib bic bie bii bik bio bir bis bit bkb bkc bke bkk bko bkr bks bkt bob boc boe boi bok boo bor bos bot brb bre bri brk bro brr brs brt bsb bsc bse bsi bsk bso bsr bss bst btb btc bte bti btk bto btr bts btt c-- cbb cbc cbe cbi cbk cbo cbr cbs cbt ccb ccc cce cci cck cco ccr ccs cct ce- ceb cec cee cei cek ceo cer ces cet ci- cib cic cie cii cik cio cir cis cit ckb ckc cki cko cks ckt co- cob coc coe coi cok coo cor cos cot crb crc cre cri crk cro crr crs crt csb csc cse csi csk cso csr css cst ctb ctc cte cti ctk cto ctr cts ctt ebb ebc ebe ebi ebk ebo ebr ebs ebt ec- ecb ecc ece eci eck eco ecr ecs ect eeb eec eee eek eeo eer ees eet eib eic eie eii eik eio eir eis eit ekb ekc eke eki eko ekr eks ekt eo- eob eoc eoe eoi eok eoo eor eos eot erb erc ere eri erk ero err ers ert es- esb esc ese esi esk eso esr ess est etb etc ete eti etk eto etr ets ett ibb ibc ibe ibi ibk ibo ibr ibs ibt icb icc ice ici ick ico icr ics ict ie- iec iee iei iek ier ies iet iib iic iie iii iio iir iis iit ikb ikc ike iki ikk iko ikr iks ikt io- iob ioc ioe ioi ioo ior ios iot ir- irb irc ire iri irk iro irr irs irt is- isb isc ise isi isk iso isr iss ist itb itc ite iti itk ito its itt k-t kbb kbc kbe kbi kbk kbo kbr kbs kcb kcc kce kci kck kcr kcs kct ke- keb kec kee kei kek keo ker kes ket kib kic kie kii kik kio kir kis kit kkb kkc kke kki kkk kkr kks kkt kob koc koe koi kok koo kor kos kot krc kri krk kro krr krs krt ksb ksc kse ksi ksk kso ksr kss kst ktb ktc kte ktk kto ktr kts ktt o-i ob- obb obc obe obi obk obo obr obs obt oc- ocb occ oci ock oco ocr ocs oct oeb oec oee oei oeo oer oes oet oib oic oie oii oik oio oir ois oit okb okc oke oki okk oko okr oks oo- oob ooc ooi ook ooo oor oos oot or- orb orc ore ori ork oro orr ors ort os- osb osc ose osi osk oso osr oss ost ot- otb otc ote oti otk oto otr ots ott rbb rbc rbe rbi rbk rbo rbr rbs rbt rcb rcc rce rci rco rcr rcs rct re- reb rec ree rei rek reo rer res ret rib ric rie rii rik rio rir ris rit rkb rkc rke rkk rko rks rkt rob roc roe roi rok roo ror ros rot rrb rrc rri rrk rrr rrs rrt rsb rsc rse rsi rsk rso rsr rss rst rtb rtc rte rti rtk rto rtr rts rtt sbb sbc sbe sbi sbk sbo sbr sbs sbt scb scc sce sci sck sco scr scs sct se- seb sec see sei sek seo ser ses set sib sic sie sii sik sio sir sis sit sk- skb skc ske ski skk sko skr sks skt sob soc soe soi sok soo sor sos sot sr- srb src sre sri srk sro srr srs srt ss- ssb ssc sse ssi ssk sso ssr sss sst stb stc ste sti stk sto str sts stt tbb tbc tbe tbi tbk tbo tbr tbs tbt tcb tcc tce tci tck tco tcr tcs tct te- teb tec tee tei tek teo ter tes tet tib tic tie tii tik tio tir tis tit tkb tkc tke tkk tko tkr tks tkt to- tob toc toe toi tok too tor tos tot trb trc tre tri trk tro trr trs trt tsb tsc tse tsi tsk tso tsr tss tst ttb ttc tte tti ttk tto ttr tts ttt