a-a a-b a-i aaa aab aad aai aas ab- aba abb abd abi abs ad- ada adb add adi ads ai- aia aib aid aii ais as- asa asb asd asi ass baa bab bad bai bas bba bbb bbd bbi bbs bda bdb bdd bdi bds bi- bia bib bid bii bis bsa bsb bsd bsi bss daa dab dad dai das dba dbb dbd dbi dbs dda ddb ddd ddi dds di- dia dib did dii dis dsa dsb dsd dsi dss i-d ia- iaa iab iad iai ias iba ibb ibd ibi ibs ida idb idd idi ids iia iib iid iii iis is- isa isb isd isi iss saa sab sad sai sas sba sbb sbd sbi sbs sda sdb sdd sdi sds sia sib sid sii sis ss- ssa ssb ssd ssi sss