a-a a-b a-t aaa aab aad aak aao aar aat ab- aba abb abd abk abo abr abt ad- ada adb add adk ado adr adt aka akb akd akk ako akr aoa aob aod aok aoo aor aot ar- ara arb ard ark aro arr art at- ata atb atd ato atr att baa bab bad bak bao bar bat bba bbb bbd bbk bbo bbr bbt bda bdb bdd bdk bdo bdr bdt bka bkb bkk bko bkr bkt boa bob bod bok boo bor bot bra brb brd brk bro brr brt bta btb btd btk bto btr btt daa dab dad dak dao dar dat dba dbb dbd dbk dbo dbr dbt dda ddb ddd ddk ddo ddr ddt dka dkb dkk dko dkr dkt doa dob dod dok doo dor dot dra drb drd drk dro drr drt dta dtb dtd dtk dto dtr dtt k-t ka- kaa kab kad kak kao kar kat kba kbb kbd kbk kbo kbr kda kdb kdk kdo kdr kdt kkb kkk kkr kkt koa kob kod kok koo kor kot kra krd krk kro krr krt kta ktb ktk kto ktr ktt oaa oab oad oak oao oar oat ob- oba obb obd obk obo obr obt oda odb odd odo odr odt oka okb okd okk oko okr oo- ooa oob ood ook ooo oor oot or- ora orb ord ork oro orr ort ot- ota otb otd otk oto otr ott ra- raa rab rad rak rao rar rat rba rbb rbd rbk rbo rbr rbt rda rdb rdd rdo rdr rdt rkb rkk rko rkt roa rob rod rok roo ror rot rra rrb rrd rrk rrr rrt rta rtb rtd rtk rto rtr rtt taa tab tad tak tao tar tat tba tbb tbd tbk tbo tbr tbt tda tdb tdd tdk tdo tdr tdt tka tkb tkk tko tkr tkt to- toa tob tod tok too tor tot tra trb trd trk tro trr trt tta ttb ttd ttk tto ttr ttt