-al -ol a-a a-b aaa aab aal aao aar ab- aba abb abl abo abr al- ala alb all alo alr aoa aob aol aoo aor ar- ara arb arl aro arr baa bab bal bao bar bba bbb bbl bbo bbr bla blb bll blo blr boa bob bol boo bor bra brb brl bro brr la- laa lab lal lao lar lba lbb lbl lbo lbr lla llb lll llo llr loa lob lol loo lor lra lrb lro lrr oaa oab oal oao oar ob- oba obb obl obo obr ola olb oll olo oo- ooa oob ool ooo oor or- ora orb orl oro orr ra- raa rab ral rao rar rba rbb rbl rbo rbr rla rll rlo rlr roa rob rol roo ror rra rrb rrl rrr