a-a a-b a-i aaa aab aae aai aao aas ab- aba abb abe abi abo abs aea aeb aee aei aeo aes ai- aia aib aie aii aio ais aoa aob aoe aoi aoo aos as- asa asb ase asi aso ass baa bab bae bai bao bas bba bbb bbe bbi bbo bbs be- bea beb bee bei beo bes bi- bia bib bie bii bio bis boa bob boe boi boo bos bsa bsb bse bsi bso bss eaa eab eae eai eao eas eba ebb ebe ebi ebo ebs eea eeb eee eeo ees eia eib eie eii eio eis eo- eoa eob eoe eoi eoo eos es- esa esb ese esi eso ess ia- iaa iab iae iai iao ias iba ibb ibe ibi ibo ibs ie- iea iee iei ies iia iib iie iii iio iis io- ioa iob ioe ioi ioo ios is- isa isb ise isi iso iss o-i oaa oab oae oai oao oas ob- oba obb obe obi obo obs oea oeb oee oei oeo oes oia oib oie oii oio ois oo- ooa oob ooi ooo oos os- osa osb ose osi oso oss saa sab sae sai sao sas sba sbb sbe sbi sbo sbs se- sea seb see sei seo ses sia sib sie sii sio sis soa sob soe soi soo sos ss- ssa ssb sse ssi sso sss