-al -ol a-a a-b a-c aaa aab aac aal aao aar ab- aba abb abc abl abo abr ac- aca acb acc acl aco acr al- ala alb alc all alo alr aoa aob aoc aol aoo aor ar- ara arb arc arl aro arr baa bab bac bal bao bar bba bbb bbc bbl bbo bbr bca bcb bcc bcl bco bcr bla blb blc bll blo blr boa bob boc bol boo bor bra brb brl bro brr c-- caa cab cac cal cao car cba cbb cbc cbl cbo cbr cca ccb ccc ccl cco ccr cl- cla clb clc cll clo clr co- coa cob coc col coo cor cra crb crc crl cro crr la- laa lab lac lal lao lar lba lbb lbc lbl lbo lbr lca lcb lcc lcl lco lcr lla llb llc lll llo llr loa lob loc lol loo lor lra lrb lrc lro lrr oaa oab oac oal oao oar ob- oba obb obc obl obo obr oc- oca ocb occ ocl oco ocr ola olb olc oll olo oo- ooa oob ooc ool ooo oor or- ora orb orc orl oro orr ra- raa rab rac ral rao rar rba rbb rbc rbl rbo rbr rca rcb rcc rcl rco rcr rla rlc rll rlo rlr roa rob roc rol roo ror rra rrb rrc rrl rrr