a-be aaaa aaab aaae aaap aaba aabb aabp aaea aaep aaoe aaoo aapa aapo abaa abab abae abap abb- abba abbb abbe abbo abee aboa abob aboo abpa abpp aeap aoba aopo apao apap apba apea apep apo- apoe apoo apop appa baaa baba babb babe babo bapa bape bapp bbbb bbeb beap beba bebb bebe bebo beeb beep beo- bepo boab boba bobb bobe bobo boea boee boeo boep boob booe boop bopa bope bopp bpea bpoe eaba eaop eapp ebba ebbo eboe eboo ebpo eeea eeee epaa epee eppa eppo eppp o-eo obba obbo obea oboe oepa ooaa ooba oobe oooo opap opep opo- oppa oppo paap paba paea paep papa papb pape papp pbpa peab peap peba peep pepa pepe pepo poba pobo poea poop pop- popa pope popo popp ppap ppoa pppa pppo pppp