a-be aaaa aaab aaae aaaf aaba aabb aabt aaea aafa aafb aaff aata aatf aatt abaa abab abae abaf abat abb- abba abbb abbe abbt abee abet abff abta aeaf aeta aetf aett afaa afat afee afet affa afft afta afte at-t ataa atab atae atat atea atee atef atfb atfe atta atte baaa baaf baat baba babb babe baff baft bata bate batf batt bbbb bbeb bbet beaf beat beba bebb bebe beeb beef beet befa befe beff beft beta bete bett bfta bftt btaa btaf bttb eaaf eaba eafb eata eate ebba eeea eeee eefa eefe eeta eete efab efet effa eft- efta etat etee etfa etfb etfe etta ette faaa faba fabe faeb fafa fafe faff fata fate fatf fatt feaf feat feba feeb feet fefe feff feta fete fett ffee ffff fftf ftea taa- taaf taat taba tabb tabe tafa tafe taff taft tata tatb tate tatt tbaf tbta teat teba teef teet teff teft teta tete tett tfae tfeb ttab ttbb ttfa ttff tttt