a-be aaaa aaab aaae aaar aaba aabb aaea aaoe aaoo aara aare aaro abaa abab abae abar abb- abba abbb abbe abbo abbr abee aber aboa abob aboo abor abra abro aeer aer- aera aero aoba aora aorb arab arae arar arba arbe area aree areo aroa arob aroe aroo aror arr- arra arre arro arrr baaa baar baba babb babe babo babr baer bar- bara barb bare baro barr bbbb bbeb bear beba bebb bebe bebo beeb beer beo- beor bera bere bero berr boab boar boba bobb bobe bobo boea boee boeo boer boob booe boor bor- bora bore boro borr brab brae brao brea breb bree breo brer broa brob broe broo bror brrr eaba eara earb eare earo ebba ebbo ebbr eber eboe eboo ebor ebro eeea eeee eera eero eora eore erba erbb erbe ereb erer erob eroe eroo erra erre erro o-eo oaer oara oare obba obbo obea ober oboe obor obra obre obro oera oere ooaa ooba oobe ooer oooo oora oore orab orae orao orar orba orbb orbe orbo ore- orea oreb oreo orer oro- oroe oror orra orro raab raba rabb rabe rabo raer raob rara rarb rare raro rbbb rbbr rea- reae reao rear reba rebb rebe rebo reeb rera rere rero roab roar rob- roba robb robe robo roea roer roob roor rora rore roro rrrr