a-a a-b aaa aab aaj aao aar ab- aba abb abj abo abr aja ajb ajj ajo ajr aoa aob aoj aoo aor ar- ara arb arj aro arr baa bab baj bao bar bba bbb bbo bbr bja bjj bjr boa bob boj boo bor bra brb brj bro brr jaa jab jaj jao jar jba jbj jbo jbr jja jjb jjj jjr joa job joj joo jor jra jrb jro jrr oaa oab oaj oao oar ob- oba obb obj obo obr oja ojb ojo oo- ooa oob ooo oor or- ora orb oro orr ra- raa rab raj rao rar rba rbb rbo rbr rja rjr roa rob roj roo ror rra rrb rrr