a-ak a-ok aaaa aaab aaap aaba aabb aabp aaka aaoo aapa aapo abaa abab abak abap abb- abba abbb abbo aboa abob abok aboo abpa abpp akaa akao akap akka akko akok akpo aoba aokp aopo apak apao apap apba apo- apoo apop appa baaa baak baba babb babo bak- baka bako bapa bapp bbbb boab boak boba bobb bobo boka boko boob book boop bopa bopp kaaa kaab kaak kaap kaba kabb kabo kaka kakk kako kaoa kaok kap- kapa kapo kapp kbaa kbab kbak kbap kbba kbbb kbbk kbbo kbkb kbkk kbko kboa kbob kbok kboo kbpa kbpk kbpo kkaa kkap kkba kkbb kkbo kkkk kkoa kkob kkoo kkpk koab koak koap koba kobb kobk kobo koka kokb kokk koko kokp koob kook kooo koop kopa kopb kopp kpak kpao kpba kpbb kpkk kpoa kpob kpok kpoo kpop kppk kppo kppp obak obba obbo obkb obok okak okap okka okko okok okpo ooaa ooak ooba oooo opap opo- oppa oppo paak paap paba paka pako papa papb papp pbpa pbpk poak poba pobo poka poko pook poop pop- popa popo popp ppap ppoa pppa pppo pppp