a-a a-b aaa aab aaj aak aao aar ab- aba abb abj abk abo abr aja ajb ajj ajk ajo ajr aka akb akj akk ako akr aoa aob aoj aok aoo aor ar- ara arb arj ark aro arr baa bab baj bak bao bar bba bbb bbk bbo bbr bja bjj bjk bjr bka bkb bkk bko bkr boa bob boj bok boo bor bra brb brj brk bro brr jaa jab jaj jak jao jar jba jbj jbk jbo jbr jja jjb jjj jjk jjr jka jkb jkk jko jkr joa job joj jok joo jor jra jrb jrk jro jrr ka- kaa kab kaj kak kao kar kba kbb kbk kbo kbr kjb kjr kkb kkk kkr koa kob kok koo kor kra krk kro krr oaa oab oaj oak oao oar ob- oba obb obj obk obo obr oja ojb ojo oka okb okj okk oko okr oo- ooa oob ook ooo oor or- ora orb ork oro orr ra- raa rab raj rak rao rar rba rbb rbk rbo rbr rja rjk rjr rkb rkk rko roa rob roj rok roo ror rra rrb rrk rrr