-er a-a a-b a-c aaa aab aac aae aaj aak aar aas ab- aba abb abc abe abj abk abr abs ac- aca acb acc ace acj ack acr acs aea aeb aec aee aej aek aer aes aja ajb ajc aje ajj ajk ajr ajs aka akb akc ake akj akk akr aks ar- ara arb arc are arj ark arr ars as- asa asb asc ase asj ask asr ass baa bab bac bae baj bak bar bas bba bbb bbc bbe bbk bbr bbs bca bcb bcc bce bcj bck bcr bcs be- bea beb bec bee bek ber bes bja bjc bjj bjk bjr bjs bka bkb bkc bke bkk bkr bks bra brb bre brj brk brr brs bsa bsb bsc bse bsj bsk bsr bss c-- c-j caa cab cac cae caj cak car cas cba cbb cbc cbe cbj cbk cbr cbs cca ccb ccc cce ccj cck ccr ccs ce- cea ceb cec cee cej cek cer ces cja cjb cjc cjk cjr cjs cka ckb ckc cks cra crb crc cre crj crk crr crs csa csb csc cse csj csk csr css eaa eab eac eae eaj eak ear eas eba ebb ebc ebe ebj ebk ebr ebs ec- eca ecb ecc ece ecj eck ecr ecs eea eeb eec eee eek eer ees eja ejc eka ekb ekc eke ekr eks era erb erc ere erk err ers es- esa esb esc ese esk esr ess jaa jab jac jae jaj jak jar jas jba jbc jbj jbk jbr jbs jca jcb jcc jce jck jcr jcs jea jeb jec jee jej jek jer jes jja jjb jjc jjj jjk jjr jjs jka jkb jkk jkr jks jra jrb jrc jrk jrr jrs jsa jsb jsc jse jsj jsk jsr jss ka- kaa kab kac kae kaj kak kar kas kba kbb kbc kbe kbk kbr kbs kca kcb kcc kce kck kcr kcs ke- kea keb kec kee kek ker kes kjb kjc kje kjr kjs kkb kkc kke kkk kkr kks kra krc krk krr krs ksa ksb ksc kse ksk ksr kss ra- raa rab rac rae raj rak rar ras rba rbb rbc rbe rbk rbr rbs rca rcb rcc rce rcj rcr rcs re- rea reb rec ree rek rer res rja rjc rjk rjr rkb rkc rke rkk rks rra rrb rrc rrk rrr rrs rsa rsb rsc rse rsj rsk rsr rss saa sab sac sae saj sak sar sas sba sbb sbc sbe sbj sbk sbr sbs sca scb scc sce scj sck scr scs se- sea seb sec see sej sek ser ses sja sjb sjc sje sjj sjk sjr sjs sk- ska skb skc ske skj skk skr sks sr- sra srb src sre srj srk srr srs ss- ssa ssb ssc sse ssj ssk ssr sss