a-a a-b aaa aab aad aae aap ab- aba abb abd abe abp ad- ada adb add ade adp aea aeb aed aee aep ap- apa apb apd ape app b-p baa bab bad bae bap bba bbb bbd bbe bbp bda bdb bdd bde bdp be- bea beb bed bee bep bpa bpb bpd bpe bpp daa dab dad dae dap dba dbb dbd dbe dbp dda ddb ddd dde ddp de- dea deb ded dee dep dpa dpb dpd dpe dpp eaa eab ead eae eap eba ebb ebd ebe ebp ed- eda edb edd ede edp eea eeb eed eee eep ep- epa epb epd epe epp p-p paa pab pad pae pap pba pbb pbd pbe pbp pda pdb pdd pde pdp pea peb ped pee pep ppa ppb ppd ppe ppp