a-a a-b a-i aaa aab aad aai aap ab- aba abb abd abi abp ad- ada adb add adi adp ai- aia aib aid aii aip ap- apa apb apd api app b-p baa bab bad bai bap bba bbb bbd bbi bbp bda bdb bdd bdi bdp bi- bia bib bid bii bip bpa bpb bpd bpi bpp daa dab dad dai dap dba dbb dbd dbi dbp dda ddb ddd ddi ddp di- dia dib did dii dip dpa dpb dpd dpi dpp i-d ia- iaa iab iad iai iap iba ibb ibd ibi ibp ida idb idd idi idp iia iib iid iii iip ipa ipb ipd ipi ipp p-p paa pab pad pai pap pba pbb pbd pbi pbp pda pdb pdd pdi pdp pia pib pid pii pip ppa ppb ppd ppi ppp