aaaa aaab aaap aaas aaba aabb aabp aaoo aapa aapo aaps aasa aass abaa abab abap abas abb- abba abbb abbo abbs aboa abob aboo abos abpa abpp abps abs- absa absp abss aoba aopo aosp aoss apao apap apas apba apbs apo- apoo apop apos appa apps apsa apso apss asaa asab asao asap asas asba asbo asob asop asos aspa aspo asps assa asso assp asss baaa baas baba babb babo babs baos bapa bapp baps basa baso bass bbas bbbb bbbs boab boas boba bobb bobo bobs boob boop boos bopa bopp bops bosa boso boss bpsa bsaa bsap bsas bsos bspp oaps oass obas obba obbo obos obss ooaa ooba oooo ooos oops oosa opap opo- opos oppa oppo opps opsa osap osas osba osbp osoo osos ossa ossb osso paap paas paba paos papa papb papp paps pasa paso pasp pass pbpa pbsa pbsp poas poba pobo pobs poop poos pop- popa popo popp pops posa posb poso poss ppap ppoa ppos pppa pppo pppp ppps ppss psap psas psoa psos pspp psps pssa psso s-os saab saap saas saba sabb sabo sabs saos sapa sapo sapp saps sasa saso sass sbaa sbas sbbs sbsa sbsp soap soas soba sobo sobp sobs soop soos sopa sopo sopp sops sosa soso soss sp-a spap spas spoo spop spos spps spsa spso spsp spss ssaa ssab ssao ssap ssas ssop sspa sspo ssps sssa sssb ssss