-al a-a a-b a-c aaa aab aac aal aar aas ab- aba abb abc abl abr abs ac- aca acb acc acl acr acs al- ala alb alc all alr als ar- ara arb arc arl arr ars as- asa asb asc asl asr ass baa bab bac bal bar bas bba bbb bbc bbl bbr bbs bca bcb bcc bcl bcr bcs bla blb blc bll blr bls bra brb brl brr brs bsa bsb bsc bsl bsr bss c-- caa cab cac cal car cas cba cbb cbc cbl cbr cbs cca ccb ccc ccl ccr ccs cl- cla clb clc cll clr cls cra crb crc crl crr crs csa csb csc csl csr css la- laa lab lac lal lar las lba lbb lbc lbl lbr lbs lca lcb lcc lcl lcr lcs lla llb llc lll llr lls lra lrb lrc lrr lrs lsa lsb lsc lsl lsr lss ra- raa rab rac ral rar ras rba rbb rbc rbl rbr rbs rca rcb rcc rcl rcr rcs rla rlc rll rlr rls rra rrb rrc rrl rrr rrs rsa rsb rsc rsl rsr rss saa sab sac sal sar sas sba sbb sbc sbl sbr sbs sca scb scc scl scr scs sla slb slc sll slr sls sr- sra srb src srl srr srs ss- ssa ssb ssc ssl ssr sss