a-a a-b a-i aaa aab aad aai aar ab- aba abb abd abi abr ad- ada adb add adi adr ai- aia aib aid aii air ar- ara arb ard ari arr baa bab bad bai bar bba bbb bbd bbi bbr bda bdb bdd bdi bdr bi- bia bib bid bii bir bra brb brd bri brr daa dab dad dai dar dba dbb dbd dbi dbr dda ddb ddd ddi ddr di- dia dib did dii dir dra drb drd dri drr i-d ia- iaa iab iad iai iar iba ibb ibd ibi ibr ida idb idd idi idr iia iib iid iii iir ir- ira irb ird iri irr ra- raa rab rad rai rar rba rbb rbd rbi rbr rda rdb rdd rdi rdr ria rib rid rii rir rra rrb rrd rri rrr