a-ii aaaa aaab aaac aaaf aaai aaba aabb aabc aabi aaca aacb aacc aacf aaci aafa aafb aafc aaff aafi aaib aaic aaii abaa abab abac abaf abai abb- abba abbb abbi abca abcb abcc abcf abci abff abia abib abic acaa acab acac acai acba acca accc accf acci acfc acfi aci- acia acic acif afaa afca afcb afcc afci affa affc affi afia afib afif aiai aiba aica aicc aicf aiff aiia aiib aiic ba-i baaa baaf baba babb babi bac- baca bacc baci bafc baff baia baib baic bbbb bbci bbfc bcaa bcbc bcca bccc bcci bcfc bcia bfca biaf biba bibb bibi bica bicc bici bifa biff bifi caaa caab caac caaf caba cabf cabi cac- caca cacc caci cafa cafb cafc caff caia caib caic cbac cbbc cbca cbcc cbfb cbfc cbia ccaa ccab ccac ccaf ccai ccba ccbc ccca cccb cccc cccf ccci ccfa ccfc ccff ccfi ccic ccii cfaa cfab cfac cfbc cfca cfcb cfcf cffb cfia ciaa ciba cibc cibi cica cicc cici cifa ciff ciia ciii faaa faac faba fabi faca facc fafa fafc faff fafi fcab fcba fcca fccf fcic fcii ffcc ffff ffii fiaa fiac fiaf fiba fica ficc fifa fifc fiff fifi fiii iaaa iaac iaai iaba iaca iacc iafc iaff iaia ibac ibca ibfi ibia icaa icab icac icaf icai icbc icca iccb iccc iccf icci icfb ifaa ifac ifbb ific iiac iica iifa iiii