a-a a-b a-i aaa aab aae aaf aai ab- aba abb abe abf abi aea aeb aee aef aei af- afa afb afe aff afi ai- aia aib aie aif aii baa bab bae baf bai bba bbb bbe bbf bbi be- bea beb bee bef bei bfa bfb bfe bff bfi bi- bia bib bie bif bii eaa eab eae eaf eai eba ebb ebe ebf ebi eea eeb eee eef ef- efa efb efe eff efi eia eib eie eif eii faa fab fae faf fai fba fbb fbe fbf fbi fea feb fee fef fei ffa ffe fff ffi fia fib fie fif fii i-f ia- iaa iab iae iaf iai iba ibb ibe ibf ibi ie- iea iee ief iei ifa ifb ife iff ifi iia iib iie iif iii