-er -ic a-a a-b a-c a-i aaa aab aac aae aai aar aas aax ab- aba abb abc abe abi abr abs abx ac- aca acb acc ace aci acr acs acx aea aeb aec aee aei aer aes aex ai- aia aib aic aie aii air ais aix ar- ara arb arc are ari arr ars arx as- asa asb asc ase asi asr ass asx ax- axa axe axi axr axs axx baa bab bac bae bai bar bas bax bba bbb bbc bbe bbi bbr bbs bbx bca bcb bcc bce bci bcr bcs bcx be- bea beb bec bee bei ber bes bex bi- bia bib bic bie bii bir bis bix bra brb bre bri brr brs brx bsa bsb bsc bse bsi bsr bss bsx bxb bxi bxx c-- caa cab cac cae cai car cas cax cba cbb cbc cbe cbi cbr cbs cbx cca ccb ccc cce cci ccr ccs ccx ce- cea ceb cec cee cei cer ces cex ci- cia cib cic cie cii cir cis cix cra crb crc cre cri crr crs crx csa csb csc cse csi csr css csx cxc cxi cxr cxs cxx eaa eab eac eae eai ear eas eax eba ebb ebc ebe ebi ebr ebs ebx ec- eca ecb ecc ece eci ecr ecs ecx eea eeb eec eee eer ees eex eia eib eic eie eii eir eis eix era erb erc ere eri err ers es- esa esb esc ese esi esr ess esx ex- exa exc exe exi exr exs exx ia- iaa iab iac iae iai iar ias iba ibb ibc ibe ibi ibr ibs ibx ica icb icc ice ici icr ics ie- iea iec iee iei ier ies iex iia iib iic iie iii iir iis iix ir- ira irb irc ire iri irr irs irx is- isa isb isc ise isi isr iss ixc ixe ixi ra- raa rab rac rae rai rar ras rax rba rbb rbc rbe rbi rbr rbs rbx rca rcb rcc rce rci rcr rcs rcx re- rea reb rec ree rei rer res rex ria rib ric rie rii rir ris rix rra rrb rrc rri rrr rrs rsa rsb rsc rse rsi rsr rss rsx rxr rxs saa sab sac sae sai sar sas sax sba sbb sbc sbe sbi sbr sbs sbx sca scb scc sce sci scr scs scx se- sea seb sec see sei ser ses sex sia sib sic sie sii sir sis six sr- sra srb src sre sri srr srs srx ss- ssa ssb ssc sse ssi ssr sss ssx sxc sxi sxs xaa xac xar xas xbc xbe xbr xbx xcb xci xcr xcx xee xer xes xex xia xic xie xii xis xix xrc xrx xsa xsb xsc xsi xss xxi xxx