-ic a-a a-b a-c a-i aaa aab aac aai aap aax ab- aba abb abc abi abp abx ac- aca acb acc aci acp acx ai- aia aib aic aii aip aix ap- apa apb apc api app apx ax- axa axi axp axx b-p baa bab bac bai bap bax bba bbb bbc bbi bbp bbx bca bcb bcc bci bcp bcx bi- bia bib bic bii bip bix bpa bpb bpc bpi bpp bpx bxb bxi bxx c-- caa cab cac cai cap cax cba cbb cbc cbi cbp cbx cca ccb ccc cci ccp ccx ci- cia cib cic cii cip cix cpa cpb cpc cpi cpp cpx cxc cxi cxp cxx ia- iaa iab iac iai iap iba ibb ibc ibi ibp ibx ica icb icc ici icp iia iib iic iii iip iix ipa ipb ipc ipi ipp ipx ixc ixi p-p paa pab pac pai pap pax pba pbb pbc pbi pbp pbx pca pcb pcc pci pcp pcx pia pib pic pii pip pix ppa ppb ppc ppi ppp ppx pxc xaa xac xap xbc xbx xcb xci xcp xcx xia xic xii xix xpa xpb xpc xpp xxi xxp xxx