aaaa aaab aaap aaar aaba aabb aabp aabt aaoo aapa aapo aapt aara aaro aarp aart aata aatt abaa abab abap abar abat abb- abba abbb abbo abbr abbt aboa abob aboo abor abot abpa abpp abpr abra abro abta aoba aopo aora aorb aort apao apap apar apat apba apbr apo- apoo apop apor apot appa appr appt apra apro aprt apta aptt arab arap arar arat arba aroa arob aroo aror arpa arr- arra arro arrr arrt arta arto artr at-t ataa atab atap atar atat atob atop ator atot atpr atra atro atrp atta atto attp attr baaa baar baat baba babb babo babr bapa bapp bapt bar- bara barb baro barr bart bata bato batt bbbb bbpr boab boar boat boba bobb bobo boob boop boor boot bopa bopp bor- bora boro borr bort bota botb boto bott bpot brab brao brat broa brob broo bror brot brrr btaa btbp btob btor btrt bttb oara obba obbo obor obot obra obro ooaa ooba oooo oora oort ootb ootp opap opar opo- opor oppa oppo opra opto orab orao orar orat orba orbb orbo oro- oror orot orra orro orta orto otap otar oto- otoo otor otpp otra otro otta otto paap paar paat paba pabt papa papb papp papr par- para paro parp parr part pata pato patr patt pbar pbpa poar poat poba pobo poop poor poot pop- popa popo popp popt pora porb poro porr port pota poto pott ppap ppar ppoa pppa pppo pppp ppta pptt prao prar prat pro- proa prob proo prop prot prtp prtr ptab ptop raab raat raba rabb rabo raob raop rapa rapp rapt rara rarb raro rata rato ratp ratt rbbb rbbr roab roap roar roat rob- roba robb robo robt roob roop roor root ropa ropo rora roro rort rota roto rotr rott rpob rpta rrat rrrr rtpa rttp taa- taar taat taba tabb tabo taoa taor tapa tapo tapp tapr tapt tara tarb taro tarp tarr tart tata tatb tato tatr tatt tbar tbrb tbta tbtp toab toat toba tobo tobt tooa toor toot top- topa topo topp topt tora toro torp torr tort tota toto totr tott tpap tppa tppp tppr tptp tptr traa trab trao trap trat troa troo trop trot trpa trpp trra trtr ttab ttbb ttop tttt