-er -ic bbb bbc bbe bbi bbk bbr bbs bbx bcb bcc bce bci bck bcr bcs bcx be- beb bec bee bei bek ber bes bex bi- bib bic bie bii bik bir bis bix bkb bkc bke bkk bkr bks bkx brb bre bri brk brr brs brx bsb bsc bse bsi bsk bsr bss bsx bxb bxi bxx c-- cbb cbc cbe cbi cbk cbr cbs cbx ccb ccc cce cci cck ccr ccs ccx ce- ceb cec cee cei cek cer ces cex ci- cib cic cie cii cik cir cis cix ckb ckc cki cks ckx crb crc cre cri crk crr crs crx csb csc cse csi csk csr css csx cxc cxi cxk cxr cxs cxx ebb ebc ebe ebi ebk ebr ebs ebx ec- ecb ecc ece eci eck ecr ecs ecx eeb eec eee eek eer ees eex eib eic eie eii eik eir eis eix ekb ekc eke eki ekr eks erb erc ere eri erk err ers es- esb esc ese esi esk esr ess esx ex- exc exe exi exr exs exx ibb ibc ibe ibi ibk ibr ibs ibx icb icc ice ici ick icr ics ie- iec iee iei iek ier ies iex iib iic iie iii iir iis iix ikb ikc ike iki ikk ikr iks ikx ir- irb irc ire iri irk irr irs irx is- isb isc ise isi isk isr iss ixc ixe ixi kbb kbc kbe kbi kbk kbr kbs kbx kcb kcc kce kci kck kcr kcs kcx ke- keb kec kee kei kek ker kes kex kib kic kie kii kik kir kis kix kkb kkc kke kki kkk kkr kks krc kri krk krr krs ksb ksc kse ksi ksk ksr kss rbb rbc rbe rbi rbk rbr rbs rbx rcb rcc rce rci rcr rcs rcx re- reb rec ree rei rek rer res rex rib ric rie rii rik rir ris rix rkb rkc rke rkk rks rrb rrc rri rrk rrr rrs rsb rsc rse rsi rsk rsr rss rsx rxr rxs sbb sbc sbe sbi sbk sbr sbs sbx scb scc sce sci sck scr scs scx se- seb sec see sei sek ser ses sex sib sic sie sii sik sir sis six sk- skb skc ske ski skk skr sks skx sr- srb src sre sri srk srr srs srx ss- ssb ssc sse ssi ssk ssr sss ssx sxc sxi sxs xbc xbe xbr xbx xcb xci xcr xcx xee xer xes xex xic xie xii xis xix xkb xke xks xrc xrx xsb xsc xsi xss xxi xxx