aaaa aaab aaac aaap aaba aabb aabc aabp aaca aacb aacc aaco aacp aaoo aapa aapc aapo abaa abab abac abap abb- abba abbb abbo abca abcb abcc abcp aboa abob aboo abpa abpc abpp acaa acab acac acap acba acca accc acco accp acoa acop acpa aoba aoca aopo apac apao apap apba apca apcb apcc apco apo- apoc apoo apop appa appc baaa baba babb babo bac- baca bacc baco bapa bapc bapp bbbb bcaa bcap bcbc bcbp bcca bccc bcpp boab boac boba bobb bobo boca boco boob booc boop bopa bopp bpcp c-bo caaa caab caac caap caba cabo cac- caca cacc caco capa capb capc capo capp cbac cbbc cbca cbcc cbcp cbpc cbpp ccaa ccab ccac ccap ccba ccbc ccca cccb cccc cccp ccob ccoc ccpa ccpp coba cobb cobo coca coco cocp coob coop copa copo copp cpaa cpac cpap cpbc cpca cppa obba obbo ocab ocac ocap ocbc occa occc ocpa ocpp ooaa ooba oooo opap opca opo- oppa oppo paap paba paca paco paoc papa papb papp pbac pbcc pboc pbpa pcaa pcap pcba pcbc pcca pccc pcoa pcpb pcpp poba pobo poca poco poop pop- popa popc popo popp ppac ppap ppcc ppoa pppa pppo pppp