-er -ic a-a a-b a-c a-i aaa aab aac aae aai aar aas ab- aba abb abc abe abi abr abs ac- aca acb acc ace aci acr acs aea aeb aec aee aei aer aes ai- aia aib aic aie aii air ais ar- ara arb arc are ari arr ars as- asa asb asc ase asi asr ass baa bab bac bae bai bar bas bba bbb bbc bbe bbi bbr bbs bca bcb bcc bce bci bcr bcs be- bea beb bec bee bei ber bes bi- bia bib bic bie bii bir bis bra brb bre bri brr brs bsa bsb bsc bse bsi bsr bss c-- caa cab cac cae cai car cas cba cbb cbc cbe cbi cbr cbs cca ccb ccc cce cci ccr ccs ce- cea ceb cec cee cei cer ces ci- cia cib cic cie cii cir cis cra crb crc cre cri crr crs csa csb csc cse csi csr css eaa eab eac eae eai ear eas eba ebb ebc ebe ebi ebr ebs ec- eca ecb ecc ece eci ecr ecs eea eeb eec eee eer ees eia eib eic eie eii eir eis era erb erc ere eri err ers es- esa esb esc ese esi esr ess ia- iaa iab iac iae iai iar ias iba ibb ibc ibe ibi ibr ibs ica icb icc ice ici icr ics ie- iea iec iee iei ier ies iia iib iic iie iii iir iis ir- ira irb irc ire iri irr irs is- isa isb isc ise isi isr iss ra- raa rab rac rae rai rar ras rba rbb rbc rbe rbi rbr rbs rca rcb rcc rce rci rcr rcs re- rea reb rec ree rei rer res ria rib ric rie rii rir ris rra rrb rrc rri rrr rrs rsa rsb rsc rse rsi rsr rss saa sab sac sae sai sar sas sba sbb sbc sbe sbi sbr sbs sca scb scc sce sci scr scs se- sea seb sec see sei ser ses sia sib sic sie sii sir sis sr- sra srb src sre sri srr srs ss- ssa ssb ssc sse ssi ssr sss