a-a a-b a-i aaa aab aad aae aaf aai ab- aba abb abd abe abf abi ad- ada adb add ade adf adi aea aeb aed aee aef aei af- afa afb afd afe aff afi ai- aia aib aid aie aif aii baa bab bad bae baf bai bba bbb bbd bbe bbf bbi bda bdb bdd bde bdf bdi be- bea beb bed bee bef bei bfa bfb bfd bfe bff bfi bi- bia bib bid bie bif bii daa dab dad dae daf dai dba dbb dbd dbe dbf dbi dda ddb ddd dde ddf ddi de- dea deb ded dee def dei dfa dfb dfd dfe dff dfi di- dia dib did die dif dii eaa eab ead eae eaf eai eba ebb ebd ebe ebf ebi ed- eda edb edd ede edf edi eea eeb eed eee eef ef- efa efb efd efe eff efi eia eib eid eie eif eii faa fab fad fae faf fai fba fbb fbd fbe fbf fbi fda fdb fdd fde fdf fdi fea feb fed fee fef fei ffa ffd ffe fff ffi fia fib fid fie fif fii i-d i-f ia- iaa iab iad iae iaf iai iba ibb ibd ibe ibf ibi ida idb idd ide idf idi ie- iea ied iee ief iei ifa ifb ifd ife iff ifi iia iib iid iie iif iii